INSTRUCTION
stringlengths 1
46.3k
| RESPONSE
stringlengths 75
80.2k
|
|---|---|
Predict values for a single data point or an RDD of points
using the model trained. | def predict(self, x):
"""
Predict values for a single data point or an RDD of points
using the model trained.
"""
if isinstance(x, RDD):
return x.map(lambda v: self.predict(v))
x = _convert_to_vector(x)
margin = self.weights.dot(x) + self.intercept
if self._threshold is None:
return margin
else:
return 1 if margin > self._threshold else 0 |
Save this model to the given path. | def save(self, sc, path):
"""
Save this model to the given path.
"""
java_model = sc._jvm.org.apache.spark.mllib.classification.SVMModel(
_py2java(sc, self._coeff), self.intercept)
java_model.save(sc._jsc.sc(), path) |
Load a model from the given path. | def load(cls, sc, path):
"""
Load a model from the given path.
"""
java_model = sc._jvm.org.apache.spark.mllib.classification.SVMModel.load(
sc._jsc.sc(), path)
weights = _java2py(sc, java_model.weights())
intercept = java_model.intercept()
threshold = java_model.getThreshold().get()
model = SVMModel(weights, intercept)
model.setThreshold(threshold)
return model |
Train a Naive Bayes model given an RDD of (label, features)
vectors.
This is the Multinomial NB (U{http://tinyurl.com/lsdw6p}) which
can handle all kinds of discrete data. For example, by
converting documents into TF-IDF vectors, it can be used for
document classification. By making every vector a 0-1 vector,
it can also be used as Bernoulli NB (U{http://tinyurl.com/p7c96j6}).
The input feature values must be nonnegative.
:param data:
RDD of LabeledPoint.
:param lambda_:
The smoothing parameter.
(default: 1.0) | def train(cls, data, lambda_=1.0):
"""
Train a Naive Bayes model given an RDD of (label, features)
vectors.
This is the Multinomial NB (U{http://tinyurl.com/lsdw6p}) which
can handle all kinds of discrete data. For example, by
converting documents into TF-IDF vectors, it can be used for
document classification. By making every vector a 0-1 vector,
it can also be used as Bernoulli NB (U{http://tinyurl.com/p7c96j6}).
The input feature values must be nonnegative.
:param data:
RDD of LabeledPoint.
:param lambda_:
The smoothing parameter.
(default: 1.0)
"""
first = data.first()
if not isinstance(first, LabeledPoint):
raise ValueError("`data` should be an RDD of LabeledPoint")
labels, pi, theta = callMLlibFunc("trainNaiveBayesModel", data, lambda_)
return NaiveBayesModel(labels.toArray(), pi.toArray(), numpy.array(theta)) |
Push item onto heap, maintaining the heap invariant. | def heappush(heap, item):
"""Push item onto heap, maintaining the heap invariant."""
heap.append(item)
_siftdown(heap, 0, len(heap)-1) |
Pop the smallest item off the heap, maintaining the heap invariant. | def heappop(heap):
"""Pop the smallest item off the heap, maintaining the heap invariant."""
lastelt = heap.pop() # raises appropriate IndexError if heap is empty
if heap:
returnitem = heap[0]
heap[0] = lastelt
_siftup(heap, 0)
return returnitem
return lastelt |
Pop and return the current smallest value, and add the new item.
This is more efficient than heappop() followed by heappush(), and can be
more appropriate when using a fixed-size heap. Note that the value
returned may be larger than item! That constrains reasonable uses of
this routine unless written as part of a conditional replacement:
if item > heap[0]:
item = heapreplace(heap, item) | def heapreplace(heap, item):
"""Pop and return the current smallest value, and add the new item.
This is more efficient than heappop() followed by heappush(), and can be
more appropriate when using a fixed-size heap. Note that the value
returned may be larger than item! That constrains reasonable uses of
this routine unless written as part of a conditional replacement:
if item > heap[0]:
item = heapreplace(heap, item)
"""
returnitem = heap[0] # raises appropriate IndexError if heap is empty
heap[0] = item
_siftup(heap, 0)
return returnitem |
Fast version of a heappush followed by a heappop. | def heappushpop(heap, item):
"""Fast version of a heappush followed by a heappop."""
if heap and heap[0] < item:
item, heap[0] = heap[0], item
_siftup(heap, 0)
return item |
Transform list into a heap, in-place, in O(len(x)) time. | def heapify(x):
"""Transform list into a heap, in-place, in O(len(x)) time."""
n = len(x)
# Transform bottom-up. The largest index there's any point to looking at
# is the largest with a child index in-range, so must have 2*i + 1 < n,
# or i < (n-1)/2. If n is even = 2*j, this is (2*j-1)/2 = j-1/2 so
# j-1 is the largest, which is n//2 - 1. If n is odd = 2*j+1, this is
# (2*j+1-1)/2 = j so j-1 is the largest, and that's again n//2-1.
for i in reversed(range(n//2)):
_siftup(x, i) |
Maxheap version of a heappop. | def _heappop_max(heap):
"""Maxheap version of a heappop."""
lastelt = heap.pop() # raises appropriate IndexError if heap is empty
if heap:
returnitem = heap[0]
heap[0] = lastelt
_siftup_max(heap, 0)
return returnitem
return lastelt |
Maxheap version of a heappop followed by a heappush. | def _heapreplace_max(heap, item):
"""Maxheap version of a heappop followed by a heappush."""
returnitem = heap[0] # raises appropriate IndexError if heap is empty
heap[0] = item
_siftup_max(heap, 0)
return returnitem |
Transform list into a maxheap, in-place, in O(len(x)) time. | def _heapify_max(x):
"""Transform list into a maxheap, in-place, in O(len(x)) time."""
n = len(x)
for i in reversed(range(n//2)):
_siftup_max(x, i) |
Maxheap variant of _siftdown | def _siftdown_max(heap, startpos, pos):
'Maxheap variant of _siftdown'
newitem = heap[pos]
# Follow the path to the root, moving parents down until finding a place
# newitem fits.
while pos > startpos:
parentpos = (pos - 1) >> 1
parent = heap[parentpos]
if parent < newitem:
heap[pos] = parent
pos = parentpos
continue
break
heap[pos] = newitem |
Maxheap variant of _siftup | def _siftup_max(heap, pos):
'Maxheap variant of _siftup'
endpos = len(heap)
startpos = pos
newitem = heap[pos]
# Bubble up the larger child until hitting a leaf.
childpos = 2*pos + 1 # leftmost child position
while childpos < endpos:
# Set childpos to index of larger child.
rightpos = childpos + 1
if rightpos < endpos and not heap[rightpos] < heap[childpos]:
childpos = rightpos
# Move the larger child up.
heap[pos] = heap[childpos]
pos = childpos
childpos = 2*pos + 1
# The leaf at pos is empty now. Put newitem there, and bubble it up
# to its final resting place (by sifting its parents down).
heap[pos] = newitem
_siftdown_max(heap, startpos, pos) |
Merge multiple sorted inputs into a single sorted output.
Similar to sorted(itertools.chain(*iterables)) but returns a generator,
does not pull the data into memory all at once, and assumes that each of
the input streams is already sorted (smallest to largest).
>>> list(merge([1,3,5,7], [0,2,4,8], [5,10,15,20], [], [25]))
[0, 1, 2, 3, 4, 5, 5, 7, 8, 10, 15, 20, 25]
If *key* is not None, applies a key function to each element to determine
its sort order.
>>> list(merge(['dog', 'horse'], ['cat', 'fish', 'kangaroo'], key=len))
['dog', 'cat', 'fish', 'horse', 'kangaroo'] | def merge(iterables, key=None, reverse=False):
'''Merge multiple sorted inputs into a single sorted output.
Similar to sorted(itertools.chain(*iterables)) but returns a generator,
does not pull the data into memory all at once, and assumes that each of
the input streams is already sorted (smallest to largest).
>>> list(merge([1,3,5,7], [0,2,4,8], [5,10,15,20], [], [25]))
[0, 1, 2, 3, 4, 5, 5, 7, 8, 10, 15, 20, 25]
If *key* is not None, applies a key function to each element to determine
its sort order.
>>> list(merge(['dog', 'horse'], ['cat', 'fish', 'kangaroo'], key=len))
['dog', 'cat', 'fish', 'horse', 'kangaroo']
'''
h = []
h_append = h.append
if reverse:
_heapify = _heapify_max
_heappop = _heappop_max
_heapreplace = _heapreplace_max
direction = -1
else:
_heapify = heapify
_heappop = heappop
_heapreplace = heapreplace
direction = 1
if key is None:
for order, it in enumerate(map(iter, iterables)):
try:
h_append([next(it), order * direction, it])
except StopIteration:
pass
_heapify(h)
while len(h) > 1:
try:
while True:
value, order, it = s = h[0]
yield value
s[0] = next(it) # raises StopIteration when exhausted
_heapreplace(h, s) # restore heap condition
except StopIteration:
_heappop(h) # remove empty iterator
if h:
# fast case when only a single iterator remains
value, order, it = h[0]
yield value
for value in it:
yield value
return
for order, it in enumerate(map(iter, iterables)):
try:
value = next(it)
h_append([key(value), order * direction, value, it])
except StopIteration:
pass
_heapify(h)
while len(h) > 1:
try:
while True:
key_value, order, value, it = s = h[0]
yield value
value = next(it)
s[0] = key(value)
s[2] = value
_heapreplace(h, s)
except StopIteration:
_heappop(h)
if h:
key_value, order, value, it = h[0]
yield value
for value in it:
yield value |
Find the n smallest elements in a dataset.
Equivalent to: sorted(iterable, key=key)[:n] | def nsmallest(n, iterable, key=None):
"""Find the n smallest elements in a dataset.
Equivalent to: sorted(iterable, key=key)[:n]
"""
# Short-cut for n==1 is to use min()
if n == 1:
it = iter(iterable)
sentinel = object()
if key is None:
result = min(it, default=sentinel)
else:
result = min(it, default=sentinel, key=key)
return [] if result is sentinel else [result]
# When n>=size, it's faster to use sorted()
try:
size = len(iterable)
except (TypeError, AttributeError):
pass
else:
if n >= size:
return sorted(iterable, key=key)[:n]
# When key is none, use simpler decoration
if key is None:
it = iter(iterable)
# put the range(n) first so that zip() doesn't
# consume one too many elements from the iterator
result = [(elem, i) for i, elem in zip(range(n), it)]
if not result:
return result
_heapify_max(result)
top = result[0][0]
order = n
_heapreplace = _heapreplace_max
for elem in it:
if elem < top:
_heapreplace(result, (elem, order))
top = result[0][0]
order += 1
result.sort()
return [r[0] for r in result]
# General case, slowest method
it = iter(iterable)
result = [(key(elem), i, elem) for i, elem in zip(range(n), it)]
if not result:
return result
_heapify_max(result)
top = result[0][0]
order = n
_heapreplace = _heapreplace_max
for elem in it:
k = key(elem)
if k < top:
_heapreplace(result, (k, order, elem))
top = result[0][0]
order += 1
result.sort()
return [r[2] for r in result] |
Find the n largest elements in a dataset.
Equivalent to: sorted(iterable, key=key, reverse=True)[:n] | def nlargest(n, iterable, key=None):
"""Find the n largest elements in a dataset.
Equivalent to: sorted(iterable, key=key, reverse=True)[:n]
"""
# Short-cut for n==1 is to use max()
if n == 1:
it = iter(iterable)
sentinel = object()
if key is None:
result = max(it, default=sentinel)
else:
result = max(it, default=sentinel, key=key)
return [] if result is sentinel else [result]
# When n>=size, it's faster to use sorted()
try:
size = len(iterable)
except (TypeError, AttributeError):
pass
else:
if n >= size:
return sorted(iterable, key=key, reverse=True)[:n]
# When key is none, use simpler decoration
if key is None:
it = iter(iterable)
result = [(elem, i) for i, elem in zip(range(0, -n, -1), it)]
if not result:
return result
heapify(result)
top = result[0][0]
order = -n
_heapreplace = heapreplace
for elem in it:
if top < elem:
_heapreplace(result, (elem, order))
top = result[0][0]
order -= 1
result.sort(reverse=True)
return [r[0] for r in result]
# General case, slowest method
it = iter(iterable)
result = [(key(elem), i, elem) for i, elem in zip(range(0, -n, -1), it)]
if not result:
return result
heapify(result)
top = result[0][0]
order = -n
_heapreplace = heapreplace
for elem in it:
k = key(elem)
if top < k:
_heapreplace(result, (k, order, elem))
top = result[0][0]
order -= 1
result.sort(reverse=True)
return [r[2] for r in result] |
Compute the correlation matrix with specified method using dataset.
:param dataset:
A Dataset or a DataFrame.
:param column:
The name of the column of vectors for which the correlation coefficient needs
to be computed. This must be a column of the dataset, and it must contain
Vector objects.
:param method:
String specifying the method to use for computing correlation.
Supported: `pearson` (default), `spearman`.
:return:
A DataFrame that contains the correlation matrix of the column of vectors. This
DataFrame contains a single row and a single column of name
'$METHODNAME($COLUMN)'.
>>> from pyspark.ml.linalg import Vectors
>>> from pyspark.ml.stat import Correlation
>>> dataset = [[Vectors.dense([1, 0, 0, -2])],
... [Vectors.dense([4, 5, 0, 3])],
... [Vectors.dense([6, 7, 0, 8])],
... [Vectors.dense([9, 0, 0, 1])]]
>>> dataset = spark.createDataFrame(dataset, ['features'])
>>> pearsonCorr = Correlation.corr(dataset, 'features', 'pearson').collect()[0][0]
>>> print(str(pearsonCorr).replace('nan', 'NaN'))
DenseMatrix([[ 1. , 0.0556..., NaN, 0.4004...],
[ 0.0556..., 1. , NaN, 0.9135...],
[ NaN, NaN, 1. , NaN],
[ 0.4004..., 0.9135..., NaN, 1. ]])
>>> spearmanCorr = Correlation.corr(dataset, 'features', method='spearman').collect()[0][0]
>>> print(str(spearmanCorr).replace('nan', 'NaN'))
DenseMatrix([[ 1. , 0.1054..., NaN, 0.4 ],
[ 0.1054..., 1. , NaN, 0.9486... ],
[ NaN, NaN, 1. , NaN],
[ 0.4 , 0.9486... , NaN, 1. ]]) | def corr(dataset, column, method="pearson"):
"""
Compute the correlation matrix with specified method using dataset.
:param dataset:
A Dataset or a DataFrame.
:param column:
The name of the column of vectors for which the correlation coefficient needs
to be computed. This must be a column of the dataset, and it must contain
Vector objects.
:param method:
String specifying the method to use for computing correlation.
Supported: `pearson` (default), `spearman`.
:return:
A DataFrame that contains the correlation matrix of the column of vectors. This
DataFrame contains a single row and a single column of name
'$METHODNAME($COLUMN)'.
>>> from pyspark.ml.linalg import Vectors
>>> from pyspark.ml.stat import Correlation
>>> dataset = [[Vectors.dense([1, 0, 0, -2])],
... [Vectors.dense([4, 5, 0, 3])],
... [Vectors.dense([6, 7, 0, 8])],
... [Vectors.dense([9, 0, 0, 1])]]
>>> dataset = spark.createDataFrame(dataset, ['features'])
>>> pearsonCorr = Correlation.corr(dataset, 'features', 'pearson').collect()[0][0]
>>> print(str(pearsonCorr).replace('nan', 'NaN'))
DenseMatrix([[ 1. , 0.0556..., NaN, 0.4004...],
[ 0.0556..., 1. , NaN, 0.9135...],
[ NaN, NaN, 1. , NaN],
[ 0.4004..., 0.9135..., NaN, 1. ]])
>>> spearmanCorr = Correlation.corr(dataset, 'features', method='spearman').collect()[0][0]
>>> print(str(spearmanCorr).replace('nan', 'NaN'))
DenseMatrix([[ 1. , 0.1054..., NaN, 0.4 ],
[ 0.1054..., 1. , NaN, 0.9486... ],
[ NaN, NaN, 1. , NaN],
[ 0.4 , 0.9486... , NaN, 1. ]])
"""
sc = SparkContext._active_spark_context
javaCorrObj = _jvm().org.apache.spark.ml.stat.Correlation
args = [_py2java(sc, arg) for arg in (dataset, column, method)]
return _java2py(sc, javaCorrObj.corr(*args)) |
Given a list of metrics, provides a builder that it turns computes metrics from a column.
See the documentation of [[Summarizer]] for an example.
The following metrics are accepted (case sensitive):
- mean: a vector that contains the coefficient-wise mean.
- variance: a vector tha contains the coefficient-wise variance.
- count: the count of all vectors seen.
- numNonzeros: a vector with the number of non-zeros for each coefficients
- max: the maximum for each coefficient.
- min: the minimum for each coefficient.
- normL2: the Euclidean norm for each coefficient.
- normL1: the L1 norm of each coefficient (sum of the absolute values).
:param metrics:
metrics that can be provided.
:return:
an object of :py:class:`pyspark.ml.stat.SummaryBuilder`
Note: Currently, the performance of this interface is about 2x~3x slower then using the RDD
interface. | def metrics(*metrics):
"""
Given a list of metrics, provides a builder that it turns computes metrics from a column.
See the documentation of [[Summarizer]] for an example.
The following metrics are accepted (case sensitive):
- mean: a vector that contains the coefficient-wise mean.
- variance: a vector tha contains the coefficient-wise variance.
- count: the count of all vectors seen.
- numNonzeros: a vector with the number of non-zeros for each coefficients
- max: the maximum for each coefficient.
- min: the minimum for each coefficient.
- normL2: the Euclidean norm for each coefficient.
- normL1: the L1 norm of each coefficient (sum of the absolute values).
:param metrics:
metrics that can be provided.
:return:
an object of :py:class:`pyspark.ml.stat.SummaryBuilder`
Note: Currently, the performance of this interface is about 2x~3x slower then using the RDD
interface.
"""
sc = SparkContext._active_spark_context
js = JavaWrapper._new_java_obj("org.apache.spark.ml.stat.Summarizer.metrics",
_to_seq(sc, metrics))
return SummaryBuilder(js) |
Returns an aggregate object that contains the summary of the column with the requested
metrics.
:param featuresCol:
a column that contains features Vector object.
:param weightCol:
a column that contains weight value. Default weight is 1.0.
:return:
an aggregate column that contains the statistics. The exact content of this
structure is determined during the creation of the builder. | def summary(self, featuresCol, weightCol=None):
"""
Returns an aggregate object that contains the summary of the column with the requested
metrics.
:param featuresCol:
a column that contains features Vector object.
:param weightCol:
a column that contains weight value. Default weight is 1.0.
:return:
an aggregate column that contains the statistics. The exact content of this
structure is determined during the creation of the builder.
"""
featuresCol, weightCol = Summarizer._check_param(featuresCol, weightCol)
return Column(self._java_obj.summary(featuresCol._jc, weightCol._jc)) |
Compute the correlation (matrix) for the input RDD(s) using the
specified method.
Methods currently supported: I{pearson (default), spearman}.
If a single RDD of Vectors is passed in, a correlation matrix
comparing the columns in the input RDD is returned. Use C{method=}
to specify the method to be used for single RDD inout.
If two RDDs of floats are passed in, a single float is returned.
:param x: an RDD of vector for which the correlation matrix is to be computed,
or an RDD of float of the same cardinality as y when y is specified.
:param y: an RDD of float of the same cardinality as x.
:param method: String specifying the method to use for computing correlation.
Supported: `pearson` (default), `spearman`
:return: Correlation matrix comparing columns in x.
>>> x = sc.parallelize([1.0, 0.0, -2.0], 2)
>>> y = sc.parallelize([4.0, 5.0, 3.0], 2)
>>> zeros = sc.parallelize([0.0, 0.0, 0.0], 2)
>>> abs(Statistics.corr(x, y) - 0.6546537) < 1e-7
True
>>> Statistics.corr(x, y) == Statistics.corr(x, y, "pearson")
True
>>> Statistics.corr(x, y, "spearman")
0.5
>>> from math import isnan
>>> isnan(Statistics.corr(x, zeros))
True
>>> from pyspark.mllib.linalg import Vectors
>>> rdd = sc.parallelize([Vectors.dense([1, 0, 0, -2]), Vectors.dense([4, 5, 0, 3]),
... Vectors.dense([6, 7, 0, 8]), Vectors.dense([9, 0, 0, 1])])
>>> pearsonCorr = Statistics.corr(rdd)
>>> print(str(pearsonCorr).replace('nan', 'NaN'))
[[ 1. 0.05564149 NaN 0.40047142]
[ 0.05564149 1. NaN 0.91359586]
[ NaN NaN 1. NaN]
[ 0.40047142 0.91359586 NaN 1. ]]
>>> spearmanCorr = Statistics.corr(rdd, method="spearman")
>>> print(str(spearmanCorr).replace('nan', 'NaN'))
[[ 1. 0.10540926 NaN 0.4 ]
[ 0.10540926 1. NaN 0.9486833 ]
[ NaN NaN 1. NaN]
[ 0.4 0.9486833 NaN 1. ]]
>>> try:
... Statistics.corr(rdd, "spearman")
... print("Method name as second argument without 'method=' shouldn't be allowed.")
... except TypeError:
... pass | def corr(x, y=None, method=None):
"""
Compute the correlation (matrix) for the input RDD(s) using the
specified method.
Methods currently supported: I{pearson (default), spearman}.
If a single RDD of Vectors is passed in, a correlation matrix
comparing the columns in the input RDD is returned. Use C{method=}
to specify the method to be used for single RDD inout.
If two RDDs of floats are passed in, a single float is returned.
:param x: an RDD of vector for which the correlation matrix is to be computed,
or an RDD of float of the same cardinality as y when y is specified.
:param y: an RDD of float of the same cardinality as x.
:param method: String specifying the method to use for computing correlation.
Supported: `pearson` (default), `spearman`
:return: Correlation matrix comparing columns in x.
>>> x = sc.parallelize([1.0, 0.0, -2.0], 2)
>>> y = sc.parallelize([4.0, 5.0, 3.0], 2)
>>> zeros = sc.parallelize([0.0, 0.0, 0.0], 2)
>>> abs(Statistics.corr(x, y) - 0.6546537) < 1e-7
True
>>> Statistics.corr(x, y) == Statistics.corr(x, y, "pearson")
True
>>> Statistics.corr(x, y, "spearman")
0.5
>>> from math import isnan
>>> isnan(Statistics.corr(x, zeros))
True
>>> from pyspark.mllib.linalg import Vectors
>>> rdd = sc.parallelize([Vectors.dense([1, 0, 0, -2]), Vectors.dense([4, 5, 0, 3]),
... Vectors.dense([6, 7, 0, 8]), Vectors.dense([9, 0, 0, 1])])
>>> pearsonCorr = Statistics.corr(rdd)
>>> print(str(pearsonCorr).replace('nan', 'NaN'))
[[ 1. 0.05564149 NaN 0.40047142]
[ 0.05564149 1. NaN 0.91359586]
[ NaN NaN 1. NaN]
[ 0.40047142 0.91359586 NaN 1. ]]
>>> spearmanCorr = Statistics.corr(rdd, method="spearman")
>>> print(str(spearmanCorr).replace('nan', 'NaN'))
[[ 1. 0.10540926 NaN 0.4 ]
[ 0.10540926 1. NaN 0.9486833 ]
[ NaN NaN 1. NaN]
[ 0.4 0.9486833 NaN 1. ]]
>>> try:
... Statistics.corr(rdd, "spearman")
... print("Method name as second argument without 'method=' shouldn't be allowed.")
... except TypeError:
... pass
"""
# Check inputs to determine whether a single value or a matrix is needed for output.
# Since it's legal for users to use the method name as the second argument, we need to
# check if y is used to specify the method name instead.
if type(y) == str:
raise TypeError("Use 'method=' to specify method name.")
if not y:
return callMLlibFunc("corr", x.map(_convert_to_vector), method).toArray()
else:
return callMLlibFunc("corr", x.map(float), y.map(float), method) |
Creates a list of callables which can be called from different threads to fit and evaluate
an estimator in parallel. Each callable returns an `(index, metric)` pair.
:param est: Estimator, the estimator to be fit.
:param train: DataFrame, training data set, used for fitting.
:param eva: Evaluator, used to compute `metric`
:param validation: DataFrame, validation data set, used for evaluation.
:param epm: Sequence of ParamMap, params maps to be used during fitting & evaluation.
:param collectSubModel: Whether to collect sub model.
:return: (int, float, subModel), an index into `epm` and the associated metric value. | def _parallelFitTasks(est, train, eva, validation, epm, collectSubModel):
"""
Creates a list of callables which can be called from different threads to fit and evaluate
an estimator in parallel. Each callable returns an `(index, metric)` pair.
:param est: Estimator, the estimator to be fit.
:param train: DataFrame, training data set, used for fitting.
:param eva: Evaluator, used to compute `metric`
:param validation: DataFrame, validation data set, used for evaluation.
:param epm: Sequence of ParamMap, params maps to be used during fitting & evaluation.
:param collectSubModel: Whether to collect sub model.
:return: (int, float, subModel), an index into `epm` and the associated metric value.
"""
modelIter = est.fitMultiple(train, epm)
def singleTask():
index, model = next(modelIter)
metric = eva.evaluate(model.transform(validation, epm[index]))
return index, metric, model if collectSubModel else None
return [singleTask] * len(epm) |
Sets the given parameters in this grid to fixed values.
Accepts either a parameter dictionary or a list of (parameter, value) pairs. | def baseOn(self, *args):
"""
Sets the given parameters in this grid to fixed values.
Accepts either a parameter dictionary or a list of (parameter, value) pairs.
"""
if isinstance(args[0], dict):
self.baseOn(*args[0].items())
else:
for (param, value) in args:
self.addGrid(param, [value])
return self |
Builds and returns all combinations of parameters specified
by the param grid. | def build(self):
"""
Builds and returns all combinations of parameters specified
by the param grid.
"""
keys = self._param_grid.keys()
grid_values = self._param_grid.values()
def to_key_value_pairs(keys, values):
return [(key, key.typeConverter(value)) for key, value in zip(keys, values)]
return [dict(to_key_value_pairs(keys, prod)) for prod in itertools.product(*grid_values)] |
Return Python estimator, estimatorParamMaps, and evaluator from a Java ValidatorParams. | def _from_java_impl(cls, java_stage):
"""
Return Python estimator, estimatorParamMaps, and evaluator from a Java ValidatorParams.
"""
# Load information from java_stage to the instance.
estimator = JavaParams._from_java(java_stage.getEstimator())
evaluator = JavaParams._from_java(java_stage.getEvaluator())
epms = [estimator._transfer_param_map_from_java(epm)
for epm in java_stage.getEstimatorParamMaps()]
return estimator, epms, evaluator |
Return Java estimator, estimatorParamMaps, and evaluator from this Python instance. | def _to_java_impl(self):
"""
Return Java estimator, estimatorParamMaps, and evaluator from this Python instance.
"""
gateway = SparkContext._gateway
cls = SparkContext._jvm.org.apache.spark.ml.param.ParamMap
java_epms = gateway.new_array(cls, len(self.getEstimatorParamMaps()))
for idx, epm in enumerate(self.getEstimatorParamMaps()):
java_epms[idx] = self.getEstimator()._transfer_param_map_to_java(epm)
java_estimator = self.getEstimator()._to_java()
java_evaluator = self.getEvaluator()._to_java()
return java_estimator, java_epms, java_evaluator |
Given a Java CrossValidator, create and return a Python wrapper of it.
Used for ML persistence. | def _from_java(cls, java_stage):
"""
Given a Java CrossValidator, create and return a Python wrapper of it.
Used for ML persistence.
"""
estimator, epms, evaluator = super(CrossValidator, cls)._from_java_impl(java_stage)
numFolds = java_stage.getNumFolds()
seed = java_stage.getSeed()
parallelism = java_stage.getParallelism()
collectSubModels = java_stage.getCollectSubModels()
# Create a new instance of this stage.
py_stage = cls(estimator=estimator, estimatorParamMaps=epms, evaluator=evaluator,
numFolds=numFolds, seed=seed, parallelism=parallelism,
collectSubModels=collectSubModels)
py_stage._resetUid(java_stage.uid())
return py_stage |
Transfer this instance to a Java CrossValidator. Used for ML persistence.
:return: Java object equivalent to this instance. | def _to_java(self):
"""
Transfer this instance to a Java CrossValidator. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
estimator, epms, evaluator = super(CrossValidator, self)._to_java_impl()
_java_obj = JavaParams._new_java_obj("org.apache.spark.ml.tuning.CrossValidator", self.uid)
_java_obj.setEstimatorParamMaps(epms)
_java_obj.setEvaluator(evaluator)
_java_obj.setEstimator(estimator)
_java_obj.setSeed(self.getSeed())
_java_obj.setNumFolds(self.getNumFolds())
_java_obj.setParallelism(self.getParallelism())
_java_obj.setCollectSubModels(self.getCollectSubModels())
return _java_obj |
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
It does not copy the extra Params into the subModels.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance | def copy(self, extra=None):
"""
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
It does not copy the extra Params into the subModels.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
"""
if extra is None:
extra = dict()
bestModel = self.bestModel.copy(extra)
avgMetrics = self.avgMetrics
subModels = self.subModels
return CrossValidatorModel(bestModel, avgMetrics, subModels) |
setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,\
parallelism=1, collectSubModels=False, seed=None):
Sets params for the train validation split. | def setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,
parallelism=1, collectSubModels=False, seed=None):
"""
setParams(self, estimator=None, estimatorParamMaps=None, evaluator=None, trainRatio=0.75,\
parallelism=1, collectSubModels=False, seed=None):
Sets params for the train validation split.
"""
kwargs = self._input_kwargs
return self._set(**kwargs) |
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies creates a deep copy of
the embedded paramMap, and copies the embedded and extra parameters over.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance | def copy(self, extra=None):
"""
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies creates a deep copy of
the embedded paramMap, and copies the embedded and extra parameters over.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
"""
if extra is None:
extra = dict()
newTVS = Params.copy(self, extra)
if self.isSet(self.estimator):
newTVS.setEstimator(self.getEstimator().copy(extra))
# estimatorParamMaps remain the same
if self.isSet(self.evaluator):
newTVS.setEvaluator(self.getEvaluator().copy(extra))
return newTVS |
Given a Java TrainValidationSplit, create and return a Python wrapper of it.
Used for ML persistence. | def _from_java(cls, java_stage):
"""
Given a Java TrainValidationSplit, create and return a Python wrapper of it.
Used for ML persistence.
"""
estimator, epms, evaluator = super(TrainValidationSplit, cls)._from_java_impl(java_stage)
trainRatio = java_stage.getTrainRatio()
seed = java_stage.getSeed()
parallelism = java_stage.getParallelism()
collectSubModels = java_stage.getCollectSubModels()
# Create a new instance of this stage.
py_stage = cls(estimator=estimator, estimatorParamMaps=epms, evaluator=evaluator,
trainRatio=trainRatio, seed=seed, parallelism=parallelism,
collectSubModels=collectSubModels)
py_stage._resetUid(java_stage.uid())
return py_stage |
Transfer this instance to a Java TrainValidationSplit. Used for ML persistence.
:return: Java object equivalent to this instance. | def _to_java(self):
"""
Transfer this instance to a Java TrainValidationSplit. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
estimator, epms, evaluator = super(TrainValidationSplit, self)._to_java_impl()
_java_obj = JavaParams._new_java_obj("org.apache.spark.ml.tuning.TrainValidationSplit",
self.uid)
_java_obj.setEstimatorParamMaps(epms)
_java_obj.setEvaluator(evaluator)
_java_obj.setEstimator(estimator)
_java_obj.setTrainRatio(self.getTrainRatio())
_java_obj.setSeed(self.getSeed())
_java_obj.setParallelism(self.getParallelism())
_java_obj.setCollectSubModels(self.getCollectSubModels())
return _java_obj |
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
And, this creates a shallow copy of the validationMetrics.
It does not copy the extra Params into the subModels.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance | def copy(self, extra=None):
"""
Creates a copy of this instance with a randomly generated uid
and some extra params. This copies the underlying bestModel,
creates a deep copy of the embedded paramMap, and
copies the embedded and extra parameters over.
And, this creates a shallow copy of the validationMetrics.
It does not copy the extra Params into the subModels.
:param extra: Extra parameters to copy to the new instance
:return: Copy of this instance
"""
if extra is None:
extra = dict()
bestModel = self.bestModel.copy(extra)
validationMetrics = list(self.validationMetrics)
subModels = self.subModels
return TrainValidationSplitModel(bestModel, validationMetrics, subModels) |
Given a Java TrainValidationSplitModel, create and return a Python wrapper of it.
Used for ML persistence. | def _from_java(cls, java_stage):
"""
Given a Java TrainValidationSplitModel, create and return a Python wrapper of it.
Used for ML persistence.
"""
# Load information from java_stage to the instance.
bestModel = JavaParams._from_java(java_stage.bestModel())
estimator, epms, evaluator = super(TrainValidationSplitModel,
cls)._from_java_impl(java_stage)
# Create a new instance of this stage.
py_stage = cls(bestModel=bestModel).setEstimator(estimator)
py_stage = py_stage.setEstimatorParamMaps(epms).setEvaluator(evaluator)
if java_stage.hasSubModels():
py_stage.subModels = [JavaParams._from_java(sub_model)
for sub_model in java_stage.subModels()]
py_stage._resetUid(java_stage.uid())
return py_stage |
Transfer this instance to a Java TrainValidationSplitModel. Used for ML persistence.
:return: Java object equivalent to this instance. | def _to_java(self):
"""
Transfer this instance to a Java TrainValidationSplitModel. Used for ML persistence.
:return: Java object equivalent to this instance.
"""
sc = SparkContext._active_spark_context
# TODO: persst validation metrics as well
_java_obj = JavaParams._new_java_obj(
"org.apache.spark.ml.tuning.TrainValidationSplitModel",
self.uid,
self.bestModel._to_java(),
_py2java(sc, []))
estimator, epms, evaluator = super(TrainValidationSplitModel, self)._to_java_impl()
_java_obj.set("evaluator", evaluator)
_java_obj.set("estimator", estimator)
_java_obj.set("estimatorParamMaps", epms)
if self.subModels is not None:
java_sub_models = [sub_model._to_java() for sub_model in self.subModels]
_java_obj.setSubModels(java_sub_models)
return _java_obj |
Returns the value of Spark runtime configuration property for the given key,
assuming it is set. | def get(self, key, default=_NoValue):
"""Returns the value of Spark runtime configuration property for the given key,
assuming it is set.
"""
self._checkType(key, "key")
if default is _NoValue:
return self._jconf.get(key)
else:
if default is not None:
self._checkType(default, "default")
return self._jconf.get(key, default) |
Assert that an object is of type str. | def _checkType(self, obj, identifier):
"""Assert that an object is of type str."""
if not isinstance(obj, basestring):
raise TypeError("expected %s '%s' to be a string (was '%s')" %
(identifier, obj, type(obj).__name__)) |
Create a PySpark function by its name | def _create_function(name, doc=""):
"""Create a PySpark function by its name"""
def _(col):
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)(col._jc if isinstance(col, Column) else col)
return Column(jc)
_.__name__ = name
_.__doc__ = doc
return _ |
Similar with `_create_function` but creates a PySpark function that takes a column
(as string as well). This is mainly for PySpark functions to take strings as
column names. | def _create_function_over_column(name, doc=""):
"""Similar with `_create_function` but creates a PySpark function that takes a column
(as string as well). This is mainly for PySpark functions to take strings as
column names.
"""
def _(col):
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)(_to_java_column(col))
return Column(jc)
_.__name__ = name
_.__doc__ = doc
return _ |
Wrap the deprecated function to print out deprecation warnings | def _wrap_deprecated_function(func, message):
""" Wrap the deprecated function to print out deprecation warnings"""
def _(col):
warnings.warn(message, DeprecationWarning)
return func(col)
return functools.wraps(func)(_) |
Create a binary mathfunction by name | def _create_binary_mathfunction(name, doc=""):
""" Create a binary mathfunction by name"""
def _(col1, col2):
sc = SparkContext._active_spark_context
# For legacy reasons, the arguments here can be implicitly converted into floats,
# if they are not columns or strings.
if isinstance(col1, Column):
arg1 = col1._jc
elif isinstance(col1, basestring):
arg1 = _create_column_from_name(col1)
else:
arg1 = float(col1)
if isinstance(col2, Column):
arg2 = col2._jc
elif isinstance(col2, basestring):
arg2 = _create_column_from_name(col2)
else:
arg2 = float(col2)
jc = getattr(sc._jvm.functions, name)(arg1, arg2)
return Column(jc)
_.__name__ = name
_.__doc__ = doc
return _ |
Create a window function by name | def _create_window_function(name, doc=''):
""" Create a window function by name """
def _():
sc = SparkContext._active_spark_context
jc = getattr(sc._jvm.functions, name)()
return Column(jc)
_.__name__ = name
_.__doc__ = 'Window function: ' + doc
return _ |
Aggregate function: returns a new :class:`Column` for approximate distinct count of
column `col`.
:param rsd: maximum estimation error allowed (default = 0.05). For rsd < 0.01, it is more
efficient to use :func:`countDistinct`
>>> df.agg(approx_count_distinct(df.age).alias('distinct_ages')).collect()
[Row(distinct_ages=2)] | def approx_count_distinct(col, rsd=None):
"""Aggregate function: returns a new :class:`Column` for approximate distinct count of
column `col`.
:param rsd: maximum estimation error allowed (default = 0.05). For rsd < 0.01, it is more
efficient to use :func:`countDistinct`
>>> df.agg(approx_count_distinct(df.age).alias('distinct_ages')).collect()
[Row(distinct_ages=2)]
"""
sc = SparkContext._active_spark_context
if rsd is None:
jc = sc._jvm.functions.approx_count_distinct(_to_java_column(col))
else:
jc = sc._jvm.functions.approx_count_distinct(_to_java_column(col), rsd)
return Column(jc) |
Marks a DataFrame as small enough for use in broadcast joins. | def broadcast(df):
"""Marks a DataFrame as small enough for use in broadcast joins."""
sc = SparkContext._active_spark_context
return DataFrame(sc._jvm.functions.broadcast(df._jdf), df.sql_ctx) |
Returns a new :class:`Column` for distinct count of ``col`` or ``cols``.
>>> df.agg(countDistinct(df.age, df.name).alias('c')).collect()
[Row(c=2)]
>>> df.agg(countDistinct("age", "name").alias('c')).collect()
[Row(c=2)] | def countDistinct(col, *cols):
"""Returns a new :class:`Column` for distinct count of ``col`` or ``cols``.
>>> df.agg(countDistinct(df.age, df.name).alias('c')).collect()
[Row(c=2)]
>>> df.agg(countDistinct("age", "name").alias('c')).collect()
[Row(c=2)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.countDistinct(_to_java_column(col), _to_seq(sc, cols, _to_java_column))
return Column(jc) |
Aggregate function: returns the last value in a group.
The function by default returns the last values it sees. It will return the last non-null
value it sees when ignoreNulls is set to true. If all values are null, then null is returned.
.. note:: The function is non-deterministic because its results depends on order of rows
which may be non-deterministic after a shuffle. | def last(col, ignorenulls=False):
"""Aggregate function: returns the last value in a group.
The function by default returns the last values it sees. It will return the last non-null
value it sees when ignoreNulls is set to true. If all values are null, then null is returned.
.. note:: The function is non-deterministic because its results depends on order of rows
which may be non-deterministic after a shuffle.
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.last(_to_java_column(col), ignorenulls)
return Column(jc) |
Returns col1 if it is not NaN, or col2 if col1 is NaN.
Both inputs should be floating point columns (:class:`DoubleType` or :class:`FloatType`).
>>> df = spark.createDataFrame([(1.0, float('nan')), (float('nan'), 2.0)], ("a", "b"))
>>> df.select(nanvl("a", "b").alias("r1"), nanvl(df.a, df.b).alias("r2")).collect()
[Row(r1=1.0, r2=1.0), Row(r1=2.0, r2=2.0)] | def nanvl(col1, col2):
"""Returns col1 if it is not NaN, or col2 if col1 is NaN.
Both inputs should be floating point columns (:class:`DoubleType` or :class:`FloatType`).
>>> df = spark.createDataFrame([(1.0, float('nan')), (float('nan'), 2.0)], ("a", "b"))
>>> df.select(nanvl("a", "b").alias("r1"), nanvl(df.a, df.b).alias("r2")).collect()
[Row(r1=1.0, r2=1.0), Row(r1=2.0, r2=2.0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.nanvl(_to_java_column(col1), _to_java_column(col2))) |
Generates a random column with independent and identically distributed (i.i.d.) samples
from U[0.0, 1.0].
.. note:: The function is non-deterministic in general case.
>>> df.withColumn('rand', rand(seed=42) * 3).collect()
[Row(age=2, name=u'Alice', rand=2.4052597283576684),
Row(age=5, name=u'Bob', rand=2.3913904055683974)] | def rand(seed=None):
"""Generates a random column with independent and identically distributed (i.i.d.) samples
from U[0.0, 1.0].
.. note:: The function is non-deterministic in general case.
>>> df.withColumn('rand', rand(seed=42) * 3).collect()
[Row(age=2, name=u'Alice', rand=2.4052597283576684),
Row(age=5, name=u'Bob', rand=2.3913904055683974)]
"""
sc = SparkContext._active_spark_context
if seed is not None:
jc = sc._jvm.functions.rand(seed)
else:
jc = sc._jvm.functions.rand()
return Column(jc) |
Round the given value to `scale` decimal places using HALF_UP rounding mode if `scale` >= 0
or at integral part when `scale` < 0.
>>> spark.createDataFrame([(2.5,)], ['a']).select(round('a', 0).alias('r')).collect()
[Row(r=3.0)] | def round(col, scale=0):
"""
Round the given value to `scale` decimal places using HALF_UP rounding mode if `scale` >= 0
or at integral part when `scale` < 0.
>>> spark.createDataFrame([(2.5,)], ['a']).select(round('a', 0).alias('r')).collect()
[Row(r=3.0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.round(_to_java_column(col), scale)) |
Shift the given value numBits left.
>>> spark.createDataFrame([(21,)], ['a']).select(shiftLeft('a', 1).alias('r')).collect()
[Row(r=42)] | def shiftLeft(col, numBits):
"""Shift the given value numBits left.
>>> spark.createDataFrame([(21,)], ['a']).select(shiftLeft('a', 1).alias('r')).collect()
[Row(r=42)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.shiftLeft(_to_java_column(col), numBits)) |
(Signed) shift the given value numBits right.
>>> spark.createDataFrame([(42,)], ['a']).select(shiftRight('a', 1).alias('r')).collect()
[Row(r=21)] | def shiftRight(col, numBits):
"""(Signed) shift the given value numBits right.
>>> spark.createDataFrame([(42,)], ['a']).select(shiftRight('a', 1).alias('r')).collect()
[Row(r=21)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.shiftRight(_to_java_column(col), numBits)
return Column(jc) |
Parses the expression string into the column that it represents
>>> df.select(expr("length(name)")).collect()
[Row(length(name)=5), Row(length(name)=3)] | def expr(str):
"""Parses the expression string into the column that it represents
>>> df.select(expr("length(name)")).collect()
[Row(length(name)=5), Row(length(name)=3)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.expr(str)) |
Evaluates a list of conditions and returns one of multiple possible result expressions.
If :func:`Column.otherwise` is not invoked, None is returned for unmatched conditions.
:param condition: a boolean :class:`Column` expression.
:param value: a literal value, or a :class:`Column` expression.
>>> df.select(when(df['age'] == 2, 3).otherwise(4).alias("age")).collect()
[Row(age=3), Row(age=4)]
>>> df.select(when(df.age == 2, df.age + 1).alias("age")).collect()
[Row(age=3), Row(age=None)] | def when(condition, value):
"""Evaluates a list of conditions and returns one of multiple possible result expressions.
If :func:`Column.otherwise` is not invoked, None is returned for unmatched conditions.
:param condition: a boolean :class:`Column` expression.
:param value: a literal value, or a :class:`Column` expression.
>>> df.select(when(df['age'] == 2, 3).otherwise(4).alias("age")).collect()
[Row(age=3), Row(age=4)]
>>> df.select(when(df.age == 2, df.age + 1).alias("age")).collect()
[Row(age=3), Row(age=None)]
"""
sc = SparkContext._active_spark_context
if not isinstance(condition, Column):
raise TypeError("condition should be a Column")
v = value._jc if isinstance(value, Column) else value
jc = sc._jvm.functions.when(condition._jc, v)
return Column(jc) |
Returns the first argument-based logarithm of the second argument.
If there is only one argument, then this takes the natural logarithm of the argument.
>>> df.select(log(10.0, df.age).alias('ten')).rdd.map(lambda l: str(l.ten)[:7]).collect()
['0.30102', '0.69897']
>>> df.select(log(df.age).alias('e')).rdd.map(lambda l: str(l.e)[:7]).collect()
['0.69314', '1.60943'] | def log(arg1, arg2=None):
"""Returns the first argument-based logarithm of the second argument.
If there is only one argument, then this takes the natural logarithm of the argument.
>>> df.select(log(10.0, df.age).alias('ten')).rdd.map(lambda l: str(l.ten)[:7]).collect()
['0.30102', '0.69897']
>>> df.select(log(df.age).alias('e')).rdd.map(lambda l: str(l.e)[:7]).collect()
['0.69314', '1.60943']
"""
sc = SparkContext._active_spark_context
if arg2 is None:
jc = sc._jvm.functions.log(_to_java_column(arg1))
else:
jc = sc._jvm.functions.log(arg1, _to_java_column(arg2))
return Column(jc) |
Convert a number in a string column from one base to another.
>>> df = spark.createDataFrame([("010101",)], ['n'])
>>> df.select(conv(df.n, 2, 16).alias('hex')).collect()
[Row(hex=u'15')] | def conv(col, fromBase, toBase):
"""
Convert a number in a string column from one base to another.
>>> df = spark.createDataFrame([("010101",)], ['n'])
>>> df.select(conv(df.n, 2, 16).alias('hex')).collect()
[Row(hex=u'15')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.conv(_to_java_column(col), fromBase, toBase)) |
Window function: returns the value that is `offset` rows before the current row, and
`defaultValue` if there is less than `offset` rows before the current row. For example,
an `offset` of one will return the previous row at any given point in the window partition.
This is equivalent to the LAG function in SQL.
:param col: name of column or expression
:param offset: number of row to extend
:param default: default value | def lag(col, offset=1, default=None):
"""
Window function: returns the value that is `offset` rows before the current row, and
`defaultValue` if there is less than `offset` rows before the current row. For example,
an `offset` of one will return the previous row at any given point in the window partition.
This is equivalent to the LAG function in SQL.
:param col: name of column or expression
:param offset: number of row to extend
:param default: default value
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.lag(_to_java_column(col), offset, default)) |
Window function: returns the ntile group id (from 1 to `n` inclusive)
in an ordered window partition. For example, if `n` is 4, the first
quarter of the rows will get value 1, the second quarter will get 2,
the third quarter will get 3, and the last quarter will get 4.
This is equivalent to the NTILE function in SQL.
:param n: an integer | def ntile(n):
"""
Window function: returns the ntile group id (from 1 to `n` inclusive)
in an ordered window partition. For example, if `n` is 4, the first
quarter of the rows will get value 1, the second quarter will get 2,
the third quarter will get 3, and the last quarter will get 4.
This is equivalent to the NTILE function in SQL.
:param n: an integer
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.ntile(int(n))) |
Converts a date/timestamp/string to a value of string in the format specified by the date
format given by the second argument.
A pattern could be for instance `dd.MM.yyyy` and could return a string like '18.03.1993'. All
pattern letters of the Java class `java.time.format.DateTimeFormatter` can be used.
.. note:: Use when ever possible specialized functions like `year`. These benefit from a
specialized implementation.
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_format('dt', 'MM/dd/yyy').alias('date')).collect()
[Row(date=u'04/08/2015')] | def date_format(date, format):
"""
Converts a date/timestamp/string to a value of string in the format specified by the date
format given by the second argument.
A pattern could be for instance `dd.MM.yyyy` and could return a string like '18.03.1993'. All
pattern letters of the Java class `java.time.format.DateTimeFormatter` can be used.
.. note:: Use when ever possible specialized functions like `year`. These benefit from a
specialized implementation.
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_format('dt', 'MM/dd/yyy').alias('date')).collect()
[Row(date=u'04/08/2015')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.date_format(_to_java_column(date), format)) |
Returns the date that is `days` days after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_add(df.dt, 1).alias('next_date')).collect()
[Row(next_date=datetime.date(2015, 4, 9))] | def date_add(start, days):
"""
Returns the date that is `days` days after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(date_add(df.dt, 1).alias('next_date')).collect()
[Row(next_date=datetime.date(2015, 4, 9))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.date_add(_to_java_column(start), days)) |
Returns the number of days from `start` to `end`.
>>> df = spark.createDataFrame([('2015-04-08','2015-05-10')], ['d1', 'd2'])
>>> df.select(datediff(df.d2, df.d1).alias('diff')).collect()
[Row(diff=32)] | def datediff(end, start):
"""
Returns the number of days from `start` to `end`.
>>> df = spark.createDataFrame([('2015-04-08','2015-05-10')], ['d1', 'd2'])
>>> df.select(datediff(df.d2, df.d1).alias('diff')).collect()
[Row(diff=32)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.datediff(_to_java_column(end), _to_java_column(start))) |
Returns the date that is `months` months after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(add_months(df.dt, 1).alias('next_month')).collect()
[Row(next_month=datetime.date(2015, 5, 8))] | def add_months(start, months):
"""
Returns the date that is `months` months after `start`
>>> df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> df.select(add_months(df.dt, 1).alias('next_month')).collect()
[Row(next_month=datetime.date(2015, 5, 8))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.add_months(_to_java_column(start), months)) |
Returns number of months between dates date1 and date2.
If date1 is later than date2, then the result is positive.
If date1 and date2 are on the same day of month, or both are the last day of month,
returns an integer (time of day will be ignored).
The result is rounded off to 8 digits unless `roundOff` is set to `False`.
>>> df = spark.createDataFrame([('1997-02-28 10:30:00', '1996-10-30')], ['date1', 'date2'])
>>> df.select(months_between(df.date1, df.date2).alias('months')).collect()
[Row(months=3.94959677)]
>>> df.select(months_between(df.date1, df.date2, False).alias('months')).collect()
[Row(months=3.9495967741935485)] | def months_between(date1, date2, roundOff=True):
"""
Returns number of months between dates date1 and date2.
If date1 is later than date2, then the result is positive.
If date1 and date2 are on the same day of month, or both are the last day of month,
returns an integer (time of day will be ignored).
The result is rounded off to 8 digits unless `roundOff` is set to `False`.
>>> df = spark.createDataFrame([('1997-02-28 10:30:00', '1996-10-30')], ['date1', 'date2'])
>>> df.select(months_between(df.date1, df.date2).alias('months')).collect()
[Row(months=3.94959677)]
>>> df.select(months_between(df.date1, df.date2, False).alias('months')).collect()
[Row(months=3.9495967741935485)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.months_between(
_to_java_column(date1), _to_java_column(date2), roundOff)) |
Converts a :class:`Column` of :class:`pyspark.sql.types.StringType` or
:class:`pyspark.sql.types.TimestampType` into :class:`pyspark.sql.types.DateType`
using the optionally specified format. Specify formats according to
`DateTimeFormatter <https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html>`_. # noqa
By default, it follows casting rules to :class:`pyspark.sql.types.DateType` if the format
is omitted (equivalent to ``col.cast("date")``).
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_date(df.t).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_date(df.t, 'yyyy-MM-dd HH:mm:ss').alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))] | def to_date(col, format=None):
"""Converts a :class:`Column` of :class:`pyspark.sql.types.StringType` or
:class:`pyspark.sql.types.TimestampType` into :class:`pyspark.sql.types.DateType`
using the optionally specified format. Specify formats according to
`DateTimeFormatter <https://docs.oracle.com/javase/8/docs/api/java/time/format/DateTimeFormatter.html>`_. # noqa
By default, it follows casting rules to :class:`pyspark.sql.types.DateType` if the format
is omitted (equivalent to ``col.cast("date")``).
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_date(df.t).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
>>> df = spark.createDataFrame([('1997-02-28 10:30:00',)], ['t'])
>>> df.select(to_date(df.t, 'yyyy-MM-dd HH:mm:ss').alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
"""
sc = SparkContext._active_spark_context
if format is None:
jc = sc._jvm.functions.to_date(_to_java_column(col))
else:
jc = sc._jvm.functions.to_date(_to_java_column(col), format)
return Column(jc) |
Returns timestamp truncated to the unit specified by the format.
:param format: 'year', 'yyyy', 'yy', 'month', 'mon', 'mm',
'day', 'dd', 'hour', 'minute', 'second', 'week', 'quarter'
>>> df = spark.createDataFrame([('1997-02-28 05:02:11',)], ['t'])
>>> df.select(date_trunc('year', df.t).alias('year')).collect()
[Row(year=datetime.datetime(1997, 1, 1, 0, 0))]
>>> df.select(date_trunc('mon', df.t).alias('month')).collect()
[Row(month=datetime.datetime(1997, 2, 1, 0, 0))] | def date_trunc(format, timestamp):
"""
Returns timestamp truncated to the unit specified by the format.
:param format: 'year', 'yyyy', 'yy', 'month', 'mon', 'mm',
'day', 'dd', 'hour', 'minute', 'second', 'week', 'quarter'
>>> df = spark.createDataFrame([('1997-02-28 05:02:11',)], ['t'])
>>> df.select(date_trunc('year', df.t).alias('year')).collect()
[Row(year=datetime.datetime(1997, 1, 1, 0, 0))]
>>> df.select(date_trunc('mon', df.t).alias('month')).collect()
[Row(month=datetime.datetime(1997, 2, 1, 0, 0))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.date_trunc(format, _to_java_column(timestamp))) |
Returns the first date which is later than the value of the date column.
Day of the week parameter is case insensitive, and accepts:
"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun".
>>> df = spark.createDataFrame([('2015-07-27',)], ['d'])
>>> df.select(next_day(df.d, 'Sun').alias('date')).collect()
[Row(date=datetime.date(2015, 8, 2))] | def next_day(date, dayOfWeek):
"""
Returns the first date which is later than the value of the date column.
Day of the week parameter is case insensitive, and accepts:
"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun".
>>> df = spark.createDataFrame([('2015-07-27',)], ['d'])
>>> df.select(next_day(df.d, 'Sun').alias('date')).collect()
[Row(date=datetime.date(2015, 8, 2))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.next_day(_to_java_column(date), dayOfWeek)) |
Returns the last day of the month which the given date belongs to.
>>> df = spark.createDataFrame([('1997-02-10',)], ['d'])
>>> df.select(last_day(df.d).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))] | def last_day(date):
"""
Returns the last day of the month which the given date belongs to.
>>> df = spark.createDataFrame([('1997-02-10',)], ['d'])
>>> df.select(last_day(df.d).alias('date')).collect()
[Row(date=datetime.date(1997, 2, 28))]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.last_day(_to_java_column(date))) |
Convert time string with given pattern ('yyyy-MM-dd HH:mm:ss', by default)
to Unix time stamp (in seconds), using the default timezone and the default
locale, return null if fail.
if `timestamp` is None, then it returns current timestamp.
>>> spark.conf.set("spark.sql.session.timeZone", "America/Los_Angeles")
>>> time_df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> time_df.select(unix_timestamp('dt', 'yyyy-MM-dd').alias('unix_time')).collect()
[Row(unix_time=1428476400)]
>>> spark.conf.unset("spark.sql.session.timeZone") | def unix_timestamp(timestamp=None, format='yyyy-MM-dd HH:mm:ss'):
"""
Convert time string with given pattern ('yyyy-MM-dd HH:mm:ss', by default)
to Unix time stamp (in seconds), using the default timezone and the default
locale, return null if fail.
if `timestamp` is None, then it returns current timestamp.
>>> spark.conf.set("spark.sql.session.timeZone", "America/Los_Angeles")
>>> time_df = spark.createDataFrame([('2015-04-08',)], ['dt'])
>>> time_df.select(unix_timestamp('dt', 'yyyy-MM-dd').alias('unix_time')).collect()
[Row(unix_time=1428476400)]
>>> spark.conf.unset("spark.sql.session.timeZone")
"""
sc = SparkContext._active_spark_context
if timestamp is None:
return Column(sc._jvm.functions.unix_timestamp())
return Column(sc._jvm.functions.unix_timestamp(_to_java_column(timestamp), format)) |
This is a common function for databases supporting TIMESTAMP WITHOUT TIMEZONE. This function
takes a timestamp which is timezone-agnostic, and interprets it as a timestamp in UTC, and
renders that timestamp as a timestamp in the given time zone.
However, timestamp in Spark represents number of microseconds from the Unix epoch, which is not
timezone-agnostic. So in Spark this function just shift the timestamp value from UTC timezone to
the given timezone.
This function may return confusing result if the input is a string with timezone, e.g.
'2018-03-13T06:18:23+00:00'. The reason is that, Spark firstly cast the string to timestamp
according to the timezone in the string, and finally display the result by converting the
timestamp to string according to the session local timezone.
:param timestamp: the column that contains timestamps
:param tz: a string that has the ID of timezone, e.g. "GMT", "America/Los_Angeles", etc
.. versionchanged:: 2.4
`tz` can take a :class:`Column` containing timezone ID strings.
>>> df = spark.createDataFrame([('1997-02-28 10:30:00', 'JST')], ['ts', 'tz'])
>>> df.select(from_utc_timestamp(df.ts, "PST").alias('local_time')).collect()
[Row(local_time=datetime.datetime(1997, 2, 28, 2, 30))]
>>> df.select(from_utc_timestamp(df.ts, df.tz).alias('local_time')).collect()
[Row(local_time=datetime.datetime(1997, 2, 28, 19, 30))]
.. note:: Deprecated in 3.0. See SPARK-25496 | def from_utc_timestamp(timestamp, tz):
"""
This is a common function for databases supporting TIMESTAMP WITHOUT TIMEZONE. This function
takes a timestamp which is timezone-agnostic, and interprets it as a timestamp in UTC, and
renders that timestamp as a timestamp in the given time zone.
However, timestamp in Spark represents number of microseconds from the Unix epoch, which is not
timezone-agnostic. So in Spark this function just shift the timestamp value from UTC timezone to
the given timezone.
This function may return confusing result if the input is a string with timezone, e.g.
'2018-03-13T06:18:23+00:00'. The reason is that, Spark firstly cast the string to timestamp
according to the timezone in the string, and finally display the result by converting the
timestamp to string according to the session local timezone.
:param timestamp: the column that contains timestamps
:param tz: a string that has the ID of timezone, e.g. "GMT", "America/Los_Angeles", etc
.. versionchanged:: 2.4
`tz` can take a :class:`Column` containing timezone ID strings.
>>> df = spark.createDataFrame([('1997-02-28 10:30:00', 'JST')], ['ts', 'tz'])
>>> df.select(from_utc_timestamp(df.ts, "PST").alias('local_time')).collect()
[Row(local_time=datetime.datetime(1997, 2, 28, 2, 30))]
>>> df.select(from_utc_timestamp(df.ts, df.tz).alias('local_time')).collect()
[Row(local_time=datetime.datetime(1997, 2, 28, 19, 30))]
.. note:: Deprecated in 3.0. See SPARK-25496
"""
warnings.warn("Deprecated in 3.0. See SPARK-25496", DeprecationWarning)
sc = SparkContext._active_spark_context
if isinstance(tz, Column):
tz = _to_java_column(tz)
return Column(sc._jvm.functions.from_utc_timestamp(_to_java_column(timestamp), tz)) |
Bucketize rows into one or more time windows given a timestamp specifying column. Window
starts are inclusive but the window ends are exclusive, e.g. 12:05 will be in the window
[12:05,12:10) but not in [12:00,12:05). Windows can support microsecond precision. Windows in
the order of months are not supported.
The time column must be of :class:`pyspark.sql.types.TimestampType`.
Durations are provided as strings, e.g. '1 second', '1 day 12 hours', '2 minutes'. Valid
interval strings are 'week', 'day', 'hour', 'minute', 'second', 'millisecond', 'microsecond'.
If the ``slideDuration`` is not provided, the windows will be tumbling windows.
The startTime is the offset with respect to 1970-01-01 00:00:00 UTC with which to start
window intervals. For example, in order to have hourly tumbling windows that start 15 minutes
past the hour, e.g. 12:15-13:15, 13:15-14:15... provide `startTime` as `15 minutes`.
The output column will be a struct called 'window' by default with the nested columns 'start'
and 'end', where 'start' and 'end' will be of :class:`pyspark.sql.types.TimestampType`.
>>> df = spark.createDataFrame([("2016-03-11 09:00:07", 1)]).toDF("date", "val")
>>> w = df.groupBy(window("date", "5 seconds")).agg(sum("val").alias("sum"))
>>> w.select(w.window.start.cast("string").alias("start"),
... w.window.end.cast("string").alias("end"), "sum").collect()
[Row(start=u'2016-03-11 09:00:05', end=u'2016-03-11 09:00:10', sum=1)] | def window(timeColumn, windowDuration, slideDuration=None, startTime=None):
"""Bucketize rows into one or more time windows given a timestamp specifying column. Window
starts are inclusive but the window ends are exclusive, e.g. 12:05 will be in the window
[12:05,12:10) but not in [12:00,12:05). Windows can support microsecond precision. Windows in
the order of months are not supported.
The time column must be of :class:`pyspark.sql.types.TimestampType`.
Durations are provided as strings, e.g. '1 second', '1 day 12 hours', '2 minutes'. Valid
interval strings are 'week', 'day', 'hour', 'minute', 'second', 'millisecond', 'microsecond'.
If the ``slideDuration`` is not provided, the windows will be tumbling windows.
The startTime is the offset with respect to 1970-01-01 00:00:00 UTC with which to start
window intervals. For example, in order to have hourly tumbling windows that start 15 minutes
past the hour, e.g. 12:15-13:15, 13:15-14:15... provide `startTime` as `15 minutes`.
The output column will be a struct called 'window' by default with the nested columns 'start'
and 'end', where 'start' and 'end' will be of :class:`pyspark.sql.types.TimestampType`.
>>> df = spark.createDataFrame([("2016-03-11 09:00:07", 1)]).toDF("date", "val")
>>> w = df.groupBy(window("date", "5 seconds")).agg(sum("val").alias("sum"))
>>> w.select(w.window.start.cast("string").alias("start"),
... w.window.end.cast("string").alias("end"), "sum").collect()
[Row(start=u'2016-03-11 09:00:05', end=u'2016-03-11 09:00:10', sum=1)]
"""
def check_string_field(field, fieldName):
if not field or type(field) is not str:
raise TypeError("%s should be provided as a string" % fieldName)
sc = SparkContext._active_spark_context
time_col = _to_java_column(timeColumn)
check_string_field(windowDuration, "windowDuration")
if slideDuration and startTime:
check_string_field(slideDuration, "slideDuration")
check_string_field(startTime, "startTime")
res = sc._jvm.functions.window(time_col, windowDuration, slideDuration, startTime)
elif slideDuration:
check_string_field(slideDuration, "slideDuration")
res = sc._jvm.functions.window(time_col, windowDuration, slideDuration)
elif startTime:
check_string_field(startTime, "startTime")
res = sc._jvm.functions.window(time_col, windowDuration, windowDuration, startTime)
else:
res = sc._jvm.functions.window(time_col, windowDuration)
return Column(res) |
Calculates the hash code of given columns, and returns the result as an int column.
>>> spark.createDataFrame([('ABC',)], ['a']).select(hash('a').alias('hash')).collect()
[Row(hash=-757602832)] | def hash(*cols):
"""Calculates the hash code of given columns, and returns the result as an int column.
>>> spark.createDataFrame([('ABC',)], ['a']).select(hash('a').alias('hash')).collect()
[Row(hash=-757602832)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.hash(_to_seq(sc, cols, _to_java_column))
return Column(jc) |
Concatenates multiple input string columns together into a single string column,
using the given separator.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat_ws('-', df.s, df.d).alias('s')).collect()
[Row(s=u'abcd-123')] | def concat_ws(sep, *cols):
"""
Concatenates multiple input string columns together into a single string column,
using the given separator.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat_ws('-', df.s, df.d).alias('s')).collect()
[Row(s=u'abcd-123')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.concat_ws(sep, _to_seq(sc, cols, _to_java_column))) |
Computes the first argument into a string from a binary using the provided character set
(one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). | def decode(col, charset):
"""
Computes the first argument into a string from a binary using the provided character set
(one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16').
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.decode(_to_java_column(col), charset)) |
Formats the number X to a format like '#,--#,--#.--', rounded to d decimal places
with HALF_EVEN round mode, and returns the result as a string.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> spark.createDataFrame([(5,)], ['a']).select(format_number('a', 4).alias('v')).collect()
[Row(v=u'5.0000')] | def format_number(col, d):
"""
Formats the number X to a format like '#,--#,--#.--', rounded to d decimal places
with HALF_EVEN round mode, and returns the result as a string.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> spark.createDataFrame([(5,)], ['a']).select(format_number('a', 4).alias('v')).collect()
[Row(v=u'5.0000')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.format_number(_to_java_column(col), d)) |
Formats the arguments in printf-style and returns the result as a string column.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> df = spark.createDataFrame([(5, "hello")], ['a', 'b'])
>>> df.select(format_string('%d %s', df.a, df.b).alias('v')).collect()
[Row(v=u'5 hello')] | def format_string(format, *cols):
"""
Formats the arguments in printf-style and returns the result as a string column.
:param col: the column name of the numeric value to be formatted
:param d: the N decimal places
>>> df = spark.createDataFrame([(5, "hello")], ['a', 'b'])
>>> df.select(format_string('%d %s', df.a, df.b).alias('v')).collect()
[Row(v=u'5 hello')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.format_string(format, _to_seq(sc, cols, _to_java_column))) |
Locate the position of the first occurrence of substr column in the given string.
Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(instr(df.s, 'b').alias('s')).collect()
[Row(s=2)] | def instr(str, substr):
"""
Locate the position of the first occurrence of substr column in the given string.
Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(instr(df.s, 'b').alias('s')).collect()
[Row(s=2)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.instr(_to_java_column(str), substr)) |
Substring starts at `pos` and is of length `len` when str is String type or
returns the slice of byte array that starts at `pos` in byte and is of length `len`
when str is Binary type.
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(substring(df.s, 1, 2).alias('s')).collect()
[Row(s=u'ab')] | def substring(str, pos, len):
"""
Substring starts at `pos` and is of length `len` when str is String type or
returns the slice of byte array that starts at `pos` in byte and is of length `len`
when str is Binary type.
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(substring(df.s, 1, 2).alias('s')).collect()
[Row(s=u'ab')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.substring(_to_java_column(str), pos, len)) |
Returns the substring from string str before count occurrences of the delimiter delim.
If count is positive, everything the left of the final delimiter (counting from left) is
returned. If count is negative, every to the right of the final delimiter (counting from the
right) is returned. substring_index performs a case-sensitive match when searching for delim.
>>> df = spark.createDataFrame([('a.b.c.d',)], ['s'])
>>> df.select(substring_index(df.s, '.', 2).alias('s')).collect()
[Row(s=u'a.b')]
>>> df.select(substring_index(df.s, '.', -3).alias('s')).collect()
[Row(s=u'b.c.d')] | def substring_index(str, delim, count):
"""
Returns the substring from string str before count occurrences of the delimiter delim.
If count is positive, everything the left of the final delimiter (counting from left) is
returned. If count is negative, every to the right of the final delimiter (counting from the
right) is returned. substring_index performs a case-sensitive match when searching for delim.
>>> df = spark.createDataFrame([('a.b.c.d',)], ['s'])
>>> df.select(substring_index(df.s, '.', 2).alias('s')).collect()
[Row(s=u'a.b')]
>>> df.select(substring_index(df.s, '.', -3).alias('s')).collect()
[Row(s=u'b.c.d')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.substring_index(_to_java_column(str), delim, count)) |
Computes the Levenshtein distance of the two given strings.
>>> df0 = spark.createDataFrame([('kitten', 'sitting',)], ['l', 'r'])
>>> df0.select(levenshtein('l', 'r').alias('d')).collect()
[Row(d=3)] | def levenshtein(left, right):
"""Computes the Levenshtein distance of the two given strings.
>>> df0 = spark.createDataFrame([('kitten', 'sitting',)], ['l', 'r'])
>>> df0.select(levenshtein('l', 'r').alias('d')).collect()
[Row(d=3)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.levenshtein(_to_java_column(left), _to_java_column(right))
return Column(jc) |
Locate the position of the first occurrence of substr in a string column, after position pos.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
:param substr: a string
:param str: a Column of :class:`pyspark.sql.types.StringType`
:param pos: start position (zero based)
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(locate('b', df.s, 1).alias('s')).collect()
[Row(s=2)] | def locate(substr, str, pos=1):
"""
Locate the position of the first occurrence of substr in a string column, after position pos.
.. note:: The position is not zero based, but 1 based index. Returns 0 if substr
could not be found in str.
:param substr: a string
:param str: a Column of :class:`pyspark.sql.types.StringType`
:param pos: start position (zero based)
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(locate('b', df.s, 1).alias('s')).collect()
[Row(s=2)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.locate(substr, _to_java_column(str), pos)) |
Left-pad the string column to width `len` with `pad`.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(lpad(df.s, 6, '#').alias('s')).collect()
[Row(s=u'##abcd')] | def lpad(col, len, pad):
"""
Left-pad the string column to width `len` with `pad`.
>>> df = spark.createDataFrame([('abcd',)], ['s',])
>>> df.select(lpad(df.s, 6, '#').alias('s')).collect()
[Row(s=u'##abcd')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.lpad(_to_java_column(col), len, pad)) |
Repeats a string column n times, and returns it as a new string column.
>>> df = spark.createDataFrame([('ab',)], ['s',])
>>> df.select(repeat(df.s, 3).alias('s')).collect()
[Row(s=u'ababab')] | def repeat(col, n):
"""
Repeats a string column n times, and returns it as a new string column.
>>> df = spark.createDataFrame([('ab',)], ['s',])
>>> df.select(repeat(df.s, 3).alias('s')).collect()
[Row(s=u'ababab')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.repeat(_to_java_column(col), n)) |
Splits str around matches of the given pattern.
:param str: a string expression to split
:param pattern: a string representing a regular expression. The regex string should be
a Java regular expression.
:param limit: an integer which controls the number of times `pattern` is applied.
* ``limit > 0``: The resulting array's length will not be more than `limit`, and the
resulting array's last entry will contain all input beyond the last
matched pattern.
* ``limit <= 0``: `pattern` will be applied as many times as possible, and the resulting
array can be of any size.
.. versionchanged:: 3.0
`split` now takes an optional `limit` field. If not provided, default limit value is -1.
>>> df = spark.createDataFrame([('oneAtwoBthreeC',)], ['s',])
>>> df.select(split(df.s, '[ABC]', 2).alias('s')).collect()
[Row(s=[u'one', u'twoBthreeC'])]
>>> df.select(split(df.s, '[ABC]', -1).alias('s')).collect()
[Row(s=[u'one', u'two', u'three', u''])] | def split(str, pattern, limit=-1):
"""
Splits str around matches of the given pattern.
:param str: a string expression to split
:param pattern: a string representing a regular expression. The regex string should be
a Java regular expression.
:param limit: an integer which controls the number of times `pattern` is applied.
* ``limit > 0``: The resulting array's length will not be more than `limit`, and the
resulting array's last entry will contain all input beyond the last
matched pattern.
* ``limit <= 0``: `pattern` will be applied as many times as possible, and the resulting
array can be of any size.
.. versionchanged:: 3.0
`split` now takes an optional `limit` field. If not provided, default limit value is -1.
>>> df = spark.createDataFrame([('oneAtwoBthreeC',)], ['s',])
>>> df.select(split(df.s, '[ABC]', 2).alias('s')).collect()
[Row(s=[u'one', u'twoBthreeC'])]
>>> df.select(split(df.s, '[ABC]', -1).alias('s')).collect()
[Row(s=[u'one', u'two', u'three', u''])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.split(_to_java_column(str), pattern, limit)) |
r"""Extract a specific group matched by a Java regex, from the specified string column.
If the regex did not match, or the specified group did not match, an empty string is returned.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)-(\d+)', 1).alias('d')).collect()
[Row(d=u'100')]
>>> df = spark.createDataFrame([('foo',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)', 1).alias('d')).collect()
[Row(d=u'')]
>>> df = spark.createDataFrame([('aaaac',)], ['str'])
>>> df.select(regexp_extract('str', '(a+)(b)?(c)', 2).alias('d')).collect()
[Row(d=u'')] | def regexp_extract(str, pattern, idx):
r"""Extract a specific group matched by a Java regex, from the specified string column.
If the regex did not match, or the specified group did not match, an empty string is returned.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)-(\d+)', 1).alias('d')).collect()
[Row(d=u'100')]
>>> df = spark.createDataFrame([('foo',)], ['str'])
>>> df.select(regexp_extract('str', r'(\d+)', 1).alias('d')).collect()
[Row(d=u'')]
>>> df = spark.createDataFrame([('aaaac',)], ['str'])
>>> df.select(regexp_extract('str', '(a+)(b)?(c)', 2).alias('d')).collect()
[Row(d=u'')]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.regexp_extract(_to_java_column(str), pattern, idx)
return Column(jc) |
r"""Replace all substrings of the specified string value that match regexp with rep.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_replace('str', r'(\d+)', '--').alias('d')).collect()
[Row(d=u'-----')] | def regexp_replace(str, pattern, replacement):
r"""Replace all substrings of the specified string value that match regexp with rep.
>>> df = spark.createDataFrame([('100-200',)], ['str'])
>>> df.select(regexp_replace('str', r'(\d+)', '--').alias('d')).collect()
[Row(d=u'-----')]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.regexp_replace(_to_java_column(str), pattern, replacement)
return Column(jc) |
A function translate any character in the `srcCol` by a character in `matching`.
The characters in `replace` is corresponding to the characters in `matching`.
The translate will happen when any character in the string matching with the character
in the `matching`.
>>> spark.createDataFrame([('translate',)], ['a']).select(translate('a', "rnlt", "123") \\
... .alias('r')).collect()
[Row(r=u'1a2s3ae')] | def translate(srcCol, matching, replace):
"""A function translate any character in the `srcCol` by a character in `matching`.
The characters in `replace` is corresponding to the characters in `matching`.
The translate will happen when any character in the string matching with the character
in the `matching`.
>>> spark.createDataFrame([('translate',)], ['a']).select(translate('a', "rnlt", "123") \\
... .alias('r')).collect()
[Row(r=u'1a2s3ae')]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.translate(_to_java_column(srcCol), matching, replace)) |
Collection function: returns true if the arrays contain any common non-null element; if not,
returns null if both the arrays are non-empty and any of them contains a null element; returns
false otherwise.
>>> df = spark.createDataFrame([(["a", "b"], ["b", "c"]), (["a"], ["b", "c"])], ['x', 'y'])
>>> df.select(arrays_overlap(df.x, df.y).alias("overlap")).collect()
[Row(overlap=True), Row(overlap=False)] | def arrays_overlap(a1, a2):
"""
Collection function: returns true if the arrays contain any common non-null element; if not,
returns null if both the arrays are non-empty and any of them contains a null element; returns
false otherwise.
>>> df = spark.createDataFrame([(["a", "b"], ["b", "c"]), (["a"], ["b", "c"])], ['x', 'y'])
>>> df.select(arrays_overlap(df.x, df.y).alias("overlap")).collect()
[Row(overlap=True), Row(overlap=False)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.arrays_overlap(_to_java_column(a1), _to_java_column(a2))) |
Collection function: returns an array containing all the elements in `x` from index `start`
(or starting from the end if `start` is negative) with the specified `length`.
>>> df = spark.createDataFrame([([1, 2, 3],), ([4, 5],)], ['x'])
>>> df.select(slice(df.x, 2, 2).alias("sliced")).collect()
[Row(sliced=[2, 3]), Row(sliced=[5])] | def slice(x, start, length):
"""
Collection function: returns an array containing all the elements in `x` from index `start`
(or starting from the end if `start` is negative) with the specified `length`.
>>> df = spark.createDataFrame([([1, 2, 3],), ([4, 5],)], ['x'])
>>> df.select(slice(df.x, 2, 2).alias("sliced")).collect()
[Row(sliced=[2, 3]), Row(sliced=[5])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.slice(_to_java_column(x), start, length)) |
Concatenates multiple input columns together into a single column.
The function works with strings, binary and compatible array columns.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat(df.s, df.d).alias('s')).collect()
[Row(s=u'abcd123')]
>>> df = spark.createDataFrame([([1, 2], [3, 4], [5]), ([1, 2], None, [3])], ['a', 'b', 'c'])
>>> df.select(concat(df.a, df.b, df.c).alias("arr")).collect()
[Row(arr=[1, 2, 3, 4, 5]), Row(arr=None)] | def concat(*cols):
"""
Concatenates multiple input columns together into a single column.
The function works with strings, binary and compatible array columns.
>>> df = spark.createDataFrame([('abcd','123')], ['s', 'd'])
>>> df.select(concat(df.s, df.d).alias('s')).collect()
[Row(s=u'abcd123')]
>>> df = spark.createDataFrame([([1, 2], [3, 4], [5]), ([1, 2], None, [3])], ['a', 'b', 'c'])
>>> df.select(concat(df.a, df.b, df.c).alias("arr")).collect()
[Row(arr=[1, 2, 3, 4, 5]), Row(arr=None)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.concat(_to_seq(sc, cols, _to_java_column))) |
Concatenates the elements of `column` using the `delimiter`. Null values are replaced with
`null_replacement` if set, otherwise they are ignored.
>>> df = spark.createDataFrame([(["a", "b", "c"],), (["a", None],)], ['data'])
>>> df.select(array_join(df.data, ",").alias("joined")).collect()
[Row(joined=u'a,b,c'), Row(joined=u'a')]
>>> df.select(array_join(df.data, ",", "NULL").alias("joined")).collect()
[Row(joined=u'a,b,c'), Row(joined=u'a,NULL')] | def array_join(col, delimiter, null_replacement=None):
"""
Concatenates the elements of `column` using the `delimiter`. Null values are replaced with
`null_replacement` if set, otherwise they are ignored.
>>> df = spark.createDataFrame([(["a", "b", "c"],), (["a", None],)], ['data'])
>>> df.select(array_join(df.data, ",").alias("joined")).collect()
[Row(joined=u'a,b,c'), Row(joined=u'a')]
>>> df.select(array_join(df.data, ",", "NULL").alias("joined")).collect()
[Row(joined=u'a,b,c'), Row(joined=u'a,NULL')]
"""
sc = SparkContext._active_spark_context
if null_replacement is None:
return Column(sc._jvm.functions.array_join(_to_java_column(col), delimiter))
else:
return Column(sc._jvm.functions.array_join(
_to_java_column(col), delimiter, null_replacement)) |
Collection function: Locates the position of the first occurrence of the given value
in the given array. Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if the given
value could not be found in the array.
>>> df = spark.createDataFrame([(["c", "b", "a"],), ([],)], ['data'])
>>> df.select(array_position(df.data, "a")).collect()
[Row(array_position(data, a)=3), Row(array_position(data, a)=0)] | def array_position(col, value):
"""
Collection function: Locates the position of the first occurrence of the given value
in the given array. Returns null if either of the arguments are null.
.. note:: The position is not zero based, but 1 based index. Returns 0 if the given
value could not be found in the array.
>>> df = spark.createDataFrame([(["c", "b", "a"],), ([],)], ['data'])
>>> df.select(array_position(df.data, "a")).collect()
[Row(array_position(data, a)=3), Row(array_position(data, a)=0)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.array_position(_to_java_column(col), value)) |
Collection function: Returns element of array at given index in extraction if col is array.
Returns value for the given key in extraction if col is map.
:param col: name of column containing array or map
:param extraction: index to check for in array or key to check for in map
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([(["a", "b", "c"],), ([],)], ['data'])
>>> df.select(element_at(df.data, 1)).collect()
[Row(element_at(data, 1)=u'a'), Row(element_at(data, 1)=None)]
>>> df = spark.createDataFrame([({"a": 1.0, "b": 2.0},), ({},)], ['data'])
>>> df.select(element_at(df.data, "a")).collect()
[Row(element_at(data, a)=1.0), Row(element_at(data, a)=None)] | def element_at(col, extraction):
"""
Collection function: Returns element of array at given index in extraction if col is array.
Returns value for the given key in extraction if col is map.
:param col: name of column containing array or map
:param extraction: index to check for in array or key to check for in map
.. note:: The position is not zero based, but 1 based index.
>>> df = spark.createDataFrame([(["a", "b", "c"],), ([],)], ['data'])
>>> df.select(element_at(df.data, 1)).collect()
[Row(element_at(data, 1)=u'a'), Row(element_at(data, 1)=None)]
>>> df = spark.createDataFrame([({"a": 1.0, "b": 2.0},), ({},)], ['data'])
>>> df.select(element_at(df.data, "a")).collect()
[Row(element_at(data, a)=1.0), Row(element_at(data, a)=None)]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.element_at(_to_java_column(col), extraction)) |
Collection function: Remove all elements that equal to element from the given array.
:param col: name of column containing array
:param element: element to be removed from the array
>>> df = spark.createDataFrame([([1, 2, 3, 1, 1],), ([],)], ['data'])
>>> df.select(array_remove(df.data, 1)).collect()
[Row(array_remove(data, 1)=[2, 3]), Row(array_remove(data, 1)=[])] | def array_remove(col, element):
"""
Collection function: Remove all elements that equal to element from the given array.
:param col: name of column containing array
:param element: element to be removed from the array
>>> df = spark.createDataFrame([([1, 2, 3, 1, 1],), ([],)], ['data'])
>>> df.select(array_remove(df.data, 1)).collect()
[Row(array_remove(data, 1)=[2, 3]), Row(array_remove(data, 1)=[])]
"""
sc = SparkContext._active_spark_context
return Column(sc._jvm.functions.array_remove(_to_java_column(col), element)) |
Returns a new row for each element in the given array or map.
Uses the default column name `col` for elements in the array and
`key` and `value` for elements in the map unless specified otherwise.
>>> from pyspark.sql import Row
>>> eDF = spark.createDataFrame([Row(a=1, intlist=[1,2,3], mapfield={"a": "b"})])
>>> eDF.select(explode(eDF.intlist).alias("anInt")).collect()
[Row(anInt=1), Row(anInt=2), Row(anInt=3)]
>>> eDF.select(explode(eDF.mapfield).alias("key", "value")).show()
+---+-----+
|key|value|
+---+-----+
| a| b|
+---+-----+ | def explode(col):
"""
Returns a new row for each element in the given array or map.
Uses the default column name `col` for elements in the array and
`key` and `value` for elements in the map unless specified otherwise.
>>> from pyspark.sql import Row
>>> eDF = spark.createDataFrame([Row(a=1, intlist=[1,2,3], mapfield={"a": "b"})])
>>> eDF.select(explode(eDF.intlist).alias("anInt")).collect()
[Row(anInt=1), Row(anInt=2), Row(anInt=3)]
>>> eDF.select(explode(eDF.mapfield).alias("key", "value")).show()
+---+-----+
|key|value|
+---+-----+
| a| b|
+---+-----+
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.explode(_to_java_column(col))
return Column(jc) |
Extracts json object from a json string based on json path specified, and returns json string
of the extracted json object. It will return null if the input json string is invalid.
:param col: string column in json format
:param path: path to the json object to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
>>> df.select(df.key, get_json_object(df.jstring, '$.f1').alias("c0"), \\
... get_json_object(df.jstring, '$.f2').alias("c1") ).collect()
[Row(key=u'1', c0=u'value1', c1=u'value2'), Row(key=u'2', c0=u'value12', c1=None)] | def get_json_object(col, path):
"""
Extracts json object from a json string based on json path specified, and returns json string
of the extracted json object. It will return null if the input json string is invalid.
:param col: string column in json format
:param path: path to the json object to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
>>> df.select(df.key, get_json_object(df.jstring, '$.f1').alias("c0"), \\
... get_json_object(df.jstring, '$.f2').alias("c1") ).collect()
[Row(key=u'1', c0=u'value1', c1=u'value2'), Row(key=u'2', c0=u'value12', c1=None)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.get_json_object(_to_java_column(col), path)
return Column(jc) |
Creates a new row for a json column according to the given field names.
:param col: string column in json format
:param fields: list of fields to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
>>> df.select(df.key, json_tuple(df.jstring, 'f1', 'f2')).collect()
[Row(key=u'1', c0=u'value1', c1=u'value2'), Row(key=u'2', c0=u'value12', c1=None)] | def json_tuple(col, *fields):
"""Creates a new row for a json column according to the given field names.
:param col: string column in json format
:param fields: list of fields to extract
>>> data = [("1", '''{"f1": "value1", "f2": "value2"}'''), ("2", '''{"f1": "value12"}''')]
>>> df = spark.createDataFrame(data, ("key", "jstring"))
>>> df.select(df.key, json_tuple(df.jstring, 'f1', 'f2')).collect()
[Row(key=u'1', c0=u'value1', c1=u'value2'), Row(key=u'2', c0=u'value12', c1=None)]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.json_tuple(_to_java_column(col), _to_seq(sc, fields))
return Column(jc) |
Parses a column containing a JSON string into a :class:`MapType` with :class:`StringType`
as keys type, :class:`StructType` or :class:`ArrayType` with
the specified schema. Returns `null`, in the case of an unparseable string.
:param col: string column in json format
:param schema: a StructType or ArrayType of StructType to use when parsing the json column.
:param options: options to control parsing. accepts the same options as the json datasource
.. note:: Since Spark 2.3, the DDL-formatted string or a JSON format string is also
supported for ``schema``.
>>> from pyspark.sql.types import *
>>> data = [(1, '''{"a": 1}''')]
>>> schema = StructType([StructField("a", IntegerType())])
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=Row(a=1))]
>>> df.select(from_json(df.value, "a INT").alias("json")).collect()
[Row(json=Row(a=1))]
>>> df.select(from_json(df.value, "MAP<STRING,INT>").alias("json")).collect()
[Row(json={u'a': 1})]
>>> data = [(1, '''[{"a": 1}]''')]
>>> schema = ArrayType(StructType([StructField("a", IntegerType())]))
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=[Row(a=1)])]
>>> schema = schema_of_json(lit('''{"a": 0}'''))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=Row(a=None))]
>>> data = [(1, '''[1, 2, 3]''')]
>>> schema = ArrayType(IntegerType())
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=[1, 2, 3])] | def from_json(col, schema, options={}):
"""
Parses a column containing a JSON string into a :class:`MapType` with :class:`StringType`
as keys type, :class:`StructType` or :class:`ArrayType` with
the specified schema. Returns `null`, in the case of an unparseable string.
:param col: string column in json format
:param schema: a StructType or ArrayType of StructType to use when parsing the json column.
:param options: options to control parsing. accepts the same options as the json datasource
.. note:: Since Spark 2.3, the DDL-formatted string or a JSON format string is also
supported for ``schema``.
>>> from pyspark.sql.types import *
>>> data = [(1, '''{"a": 1}''')]
>>> schema = StructType([StructField("a", IntegerType())])
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=Row(a=1))]
>>> df.select(from_json(df.value, "a INT").alias("json")).collect()
[Row(json=Row(a=1))]
>>> df.select(from_json(df.value, "MAP<STRING,INT>").alias("json")).collect()
[Row(json={u'a': 1})]
>>> data = [(1, '''[{"a": 1}]''')]
>>> schema = ArrayType(StructType([StructField("a", IntegerType())]))
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=[Row(a=1)])]
>>> schema = schema_of_json(lit('''{"a": 0}'''))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=Row(a=None))]
>>> data = [(1, '''[1, 2, 3]''')]
>>> schema = ArrayType(IntegerType())
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(from_json(df.value, schema).alias("json")).collect()
[Row(json=[1, 2, 3])]
"""
sc = SparkContext._active_spark_context
if isinstance(schema, DataType):
schema = schema.json()
elif isinstance(schema, Column):
schema = _to_java_column(schema)
jc = sc._jvm.functions.from_json(_to_java_column(col), schema, options)
return Column(jc) |
Parses a JSON string and infers its schema in DDL format.
:param json: a JSON string or a string literal containing a JSON string.
:param options: options to control parsing. accepts the same options as the JSON datasource
.. versionchanged:: 3.0
It accepts `options` parameter to control schema inferring.
>>> df = spark.range(1)
>>> df.select(schema_of_json(lit('{"a": 0}')).alias("json")).collect()
[Row(json=u'struct<a:bigint>')]
>>> schema = schema_of_json('{a: 1}', {'allowUnquotedFieldNames':'true'})
>>> df.select(schema.alias("json")).collect()
[Row(json=u'struct<a:bigint>')] | def schema_of_json(json, options={}):
"""
Parses a JSON string and infers its schema in DDL format.
:param json: a JSON string or a string literal containing a JSON string.
:param options: options to control parsing. accepts the same options as the JSON datasource
.. versionchanged:: 3.0
It accepts `options` parameter to control schema inferring.
>>> df = spark.range(1)
>>> df.select(schema_of_json(lit('{"a": 0}')).alias("json")).collect()
[Row(json=u'struct<a:bigint>')]
>>> schema = schema_of_json('{a: 1}', {'allowUnquotedFieldNames':'true'})
>>> df.select(schema.alias("json")).collect()
[Row(json=u'struct<a:bigint>')]
"""
if isinstance(json, basestring):
col = _create_column_from_literal(json)
elif isinstance(json, Column):
col = _to_java_column(json)
else:
raise TypeError("schema argument should be a column or string")
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.schema_of_json(col, options)
return Column(jc) |
Parses a CSV string and infers its schema in DDL format.
:param col: a CSV string or a string literal containing a CSV string.
:param options: options to control parsing. accepts the same options as the CSV datasource
>>> df = spark.range(1)
>>> df.select(schema_of_csv(lit('1|a'), {'sep':'|'}).alias("csv")).collect()
[Row(csv=u'struct<_c0:int,_c1:string>')]
>>> df.select(schema_of_csv('1|a', {'sep':'|'}).alias("csv")).collect()
[Row(csv=u'struct<_c0:int,_c1:string>')] | def schema_of_csv(csv, options={}):
"""
Parses a CSV string and infers its schema in DDL format.
:param col: a CSV string or a string literal containing a CSV string.
:param options: options to control parsing. accepts the same options as the CSV datasource
>>> df = spark.range(1)
>>> df.select(schema_of_csv(lit('1|a'), {'sep':'|'}).alias("csv")).collect()
[Row(csv=u'struct<_c0:int,_c1:string>')]
>>> df.select(schema_of_csv('1|a', {'sep':'|'}).alias("csv")).collect()
[Row(csv=u'struct<_c0:int,_c1:string>')]
"""
if isinstance(csv, basestring):
col = _create_column_from_literal(csv)
elif isinstance(csv, Column):
col = _to_java_column(csv)
else:
raise TypeError("schema argument should be a column or string")
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.schema_of_csv(col, options)
return Column(jc) |
Converts a column containing a :class:`StructType` into a CSV string.
Throws an exception, in the case of an unsupported type.
:param col: name of column containing a struct.
:param options: options to control converting. accepts the same options as the CSV datasource.
>>> from pyspark.sql import Row
>>> data = [(1, Row(name='Alice', age=2))]
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(to_csv(df.value).alias("csv")).collect()
[Row(csv=u'2,Alice')] | def to_csv(col, options={}):
"""
Converts a column containing a :class:`StructType` into a CSV string.
Throws an exception, in the case of an unsupported type.
:param col: name of column containing a struct.
:param options: options to control converting. accepts the same options as the CSV datasource.
>>> from pyspark.sql import Row
>>> data = [(1, Row(name='Alice', age=2))]
>>> df = spark.createDataFrame(data, ("key", "value"))
>>> df.select(to_csv(df.value).alias("csv")).collect()
[Row(csv=u'2,Alice')]
"""
sc = SparkContext._active_spark_context
jc = sc._jvm.functions.to_csv(_to_java_column(col), options)
return Column(jc) |