Repository: pandas-dev/pandas

Issue:
latest version of dateutil requires six
https://travis-ci.org/pydata/pandas/jobs/17252239

But why doesn't this show up on py3.x



Discussion:
I think that's a pypi glitch while fetching six. dateutil last release was nov/13
we'd have seen it earlier if it was the case.  


Resolving patch:
diff --git a/pandas/core/series.py b/pandas/core/series.py
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -1349,11 +1349,7 @@ def describe(self, percentile_width=50):
         -------
         desc : Series
         """
-        try:
-            from collections import Counter
-        except ImportError:  # pragma: no cover
-            # For Python < 2.7, we include a local copy of this:
-            from pandas.util.counter import Counter
+        from pandas.compat import Counter
 
         if self.dtype == object:
             names = ['count', 'unique']
diff --git a/pandas/util/counter.py b/pandas/util/counter.py
deleted file mode 100644
--- a/pandas/util/counter.py
+++ /dev/null
@@ -1,296 +0,0 @@
-# This is copied from collections in Python 2.7, for compatibility with older
-# versions of Python. It can be dropped when we depend on Python 2.7/3.1
-
-from pandas import compat
-import heapq as _heapq
-from itertools import repeat as _repeat, chain as _chain, starmap as _starmap
-from operator import itemgetter as _itemgetter
-from pandas.compat import map
-
-try:
-    from collections import Mapping
-except:
-    # ABCs were only introduced in Python 2.6, so this is a hack for Python 2.5
-    Mapping = dict
-
-
-class Counter(dict):
-    '''Dict subclass for counting hashable items.  Sometimes called a bag
-    or multiset.  Elements are stored as dictionary keys and their counts
-    are stored as dictionary values.
-
-    >>> c = Counter('abcdeabcdabcaba')  # count elements from a string
-
-    >>> c.most_common(3)                # three most common elements
-    [('a', 5), ('b', 4), ('c', 3)]
-    >>> sorted(c)                       # list all unique elements
-    ['a', 'b', 'c', 'd', 'e']
-    >>> ''.join(sorted(c.elements()))   # list elements with repetitions
-    'aaaaabbbbcccdde'
-    >>> sum(c.values())                 # total of all counts
-    15
-
-    >>> c['a']                          # count of letter 'a'
-    5
-    >>> for elem in 'shazam':           # update counts from an iterable
-    ...     c[elem] += 1                # by adding 1 to each element's count
-    >>> c['a']                          # now there are seven 'a'
-    7
-    >>> del c['b']                      # remove all 'b'
-    >>> c['b']                          # now there are zero 'b'
-    0
-
-    >>> d = Counter('simsalabim')       # make another counter
-    >>> c.update(d)                     # add in the second counter
-    >>> c['a']                          # now there are nine 'a'
-    9
-
-    >>> c.clear()                       # empty the counter
-    >>> c
-    Counter()
-
-    Note:  If a count is set to zero or reduced to zero, it will remain
-    in the counter until the entry is deleted or the counter is cleared:
-
-    >>> c = Counter('aaabbc')
-    >>> c['b'] -= 2                    # reduce the count of 'b' by two
-    >>> c.most_common()                # 'b' is still in, but its count is zero
-    [('a', 3), ('c', 1), ('b', 0)]
-
-    '''
-    # References:
-    #   http://en.wikipedia.org/wiki/Multiset
-    #   http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html
-    #   http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm
-    #   http://code.activestate.com/recipes/259174/
-    #   Knuth, TAOCP Vol. II section 4.6.3
-
-    def __init__(self, iterable=None, **kwds):
-        '''Create a new, empty Counter object.  And if given, count elements
-        from an input iterable.  Or, initialize the count from another mapping
-        of elements to their counts.
-
-        >>> c = Counter()                     # a new, empty counter
-        >>> c = Counter('gallahad')           # a new counter from an iterable
-        >>> c = Counter({'a': 4, 'b': 2})     # a new counter from a mapping
-        >>> c = Counter(a=4, b=2)             # a new counter from keyword args
-
-        '''
-        super(Counter, self).__init__()
-        self.update(iterable, **kwds)
-
-    def __missing__(self, key):
-        'The count of elements not in the Counter is zero.'
-        # Needed so that self[missing_item] does not raise KeyError
-        return 0
-
-    def most_common(self, n=None):
-        '''List the n most common elements and their counts from the most
-        common to the least.  If n is None, then list all element counts.
-
-        >>> Counter('abcdeabcdabcaba').most_common(3)
-        [('a', 5), ('b', 4), ('c', 3)]
-
-        '''
-        # Emulate Bag.sortedByCount from Smalltalk
-        if n is None:
-            return sorted(compat.iteritems(self), key=_itemgetter(1), reverse=True)
-        return _heapq.nlargest(n, compat.iteritems(self), key=_itemgetter(1))
-
-    def elements(self):
-        '''Iterator over elements repeating each as many times as its count.
-
-        >>> c = Counter('ABCABC')
-        >>> sorted(c.elements())
-        ['A', 'A', 'B', 'B', 'C', 'C']
-
-        # Knuth's example for prime factors of 1836:  2**2 * 3**3 * 17**1
-        >>> prime_factors = Counter({2: 2, 3: 3, 17: 1})
-        >>> product = 1
-        >>> for factor in prime_factors.elements():     # loop over factors
-        ...     product *= factor                       # and multiply them
-        >>> product
-        1836
-
-        Note, if an element's count has been set to zero or is a negative
-        number, elements() will ignore it.
-
-        '''
-        # Emulate Bag.do from Smalltalk and Multiset.begin from C++.
-        return _chain.from_iterable(_starmap(_repeat, compat.iteritems(self)))
-
-    # Override dict methods where necessary
-
-    @classmethod
-    def fromkeys(cls, iterable, v=None):
-        # There is no equivalent method for counters because setting v=1
-        # means that no element can have a count greater than one.
-        raise NotImplementedError(
-            'Counter.fromkeys() is undefined.  Use Counter(iterable) instead.')
-
-    def update(self, iterable=None, **kwds):
-        '''Like dict.update() but add counts instead of replacing them.
-
-        Source can be an iterable, a dictionary, or another Counter instance.
-
-        >>> c = Counter('which')
-        >>> c.update('witch')           # add elements from another iterable
-        >>> d = Counter('watch')
-        >>> c.update(d)                 # add elements from another counter
-        >>> c['h']                      # four 'h' in which, witch, and watch
-        4
-
-        '''
-        # The regular dict.update() operation makes no sense here because the
-        # replace behavior results in the some of original untouched counts
-        # being mixed-in with all of the other counts for a mismash that
-        # doesn't have a straight-forward interpretation in most counting
-        # contexts.  Instead, we implement straight-addition.  Both the inputs
-        # and outputs are allowed to contain zero and negative counts.
-
-        if iterable is not None:
-            if isinstance(iterable, Mapping):
-                if self:
-                    self_get = self.get
-                    for elem, count in compat.iteritems(iterable):
-                        self[elem] = self_get(elem, 0) + count
-                else:
-                    # fast path when counter is empty
-                    super(Counter, self).update(iterable)
-            else:
-                self_get = self.get
-                for elem in iterable:
-                    self[elem] = self_get(elem, 0) + 1
-        if kwds:
-            self.update(kwds)
-
-    def subtract(self, iterable=None, **kwds):
-        '''Like dict.update() but subtracts counts instead of replacing them.
-        Counts can be reduced below zero.  Both the inputs and outputs are
-        allowed to contain zero and negative counts.
-
-        Source can be an iterable, a dictionary, or another Counter instance.
-
-        >>> c = Counter('which')
-        >>> c.subtract('witch')             # subtract elements from another iterable
-        >>> c.subtract(Counter('watch'))    # subtract elements from another counter
-        >>> c['h']                          # 2 in which, minus 1 in witch, minus 1 in watch
-        0
-        >>> c['w']                          # 1 in which, minus 1 in witch, minus 1 in watch
-        -1
-
-        '''
-        if iterable is not None:
-            self_get = self.get
-            if isinstance(iterable, Mapping):
-                for elem, count in iterable.items():
-                    self[elem] = self_get(elem, 0) - count
-            else:
-                for elem in iterable:
-                    self[elem] = self_get(elem, 0) - 1
-        if kwds:
-            self.subtract(kwds)
-
-    def copy(self):
-        'Return a shallow copy.'
-        return self.__class__(self)
-
-    def __reduce__(self):
-        return self.__class__, (dict(self),)
-
-    def __delitem__(self, elem):
-        """
-        Like dict.__delitem__() but does not raise KeyError for missing values.
-        """
-        if elem in self:
-            super(Counter, self).__delitem__(elem)
-
-    def __repr__(self):
-        if not self:
-            return '%s()' % self.__class__.__name__
-        items = ', '.join(map('%r: %r'.__mod__, self.most_common()))
-        return '%s({%s})' % (self.__class__.__name__, items)
-
-    # Multiset-style mathematical operations discussed in:
-    #       Knuth TAOCP Volume II section 4.6.3 exercise 19
-    #       and at http://en.wikipedia.org/wiki/Multiset
-    #
-    # Outputs guaranteed to only include positive counts.
-    #
-    # To strip negative and zero counts, add-in an empty counter:
-    #       c += Counter()
-
-    def __add__(self, other):
-        '''Add counts from two counters.
-
-        >>> Counter('abbb') + Counter('bcc')
-        Counter({'b': 4, 'c': 2, 'a': 1})
-
-        '''
-        if not isinstance(other, Counter):
-            return NotImplemented
-        result = Counter()
-        for elem, count in self.items():
-            newcount = count + other[elem]
-            if newcount > 0:
-                result[elem] = newcount
-        for elem, count in other.items():
-            if elem not in self and count > 0:
-                result[elem] = count
-        return result
-
-    def __sub__(self, other):
-        ''' Subtract count, but keep only results with positive counts.
-
-        >>> Counter('abbbc') - Counter('bccd')
-        Counter({'b': 2, 'a': 1})
-
-        '''
-        if not isinstance(other, Counter):
-            return NotImplemented
-        result = Counter()
-        for elem, count in self.items():
-            newcount = count - other[elem]
-            if newcount > 0:
-                result[elem] = newcount
-        for elem, count in other.items():
-            if elem not in self and count < 0:
-                result[elem] = 0 - count
-        return result
-
-    def __or__(self, other):
-        '''Union is the maximum of value in either of the input counters.
-
-        >>> Counter('abbb') | Counter('bcc')
-        Counter({'b': 3, 'c': 2, 'a': 1})
-
-        '''
-        if not isinstance(other, Counter):
-            return NotImplemented
-        result = Counter()
-        for elem, count in self.items():
-            other_count = other[elem]
-            newcount = other_count if count < other_count else count
-            if newcount > 0:
-                result[elem] = newcount
-        for elem, count in other.items():
-            if elem not in self and count > 0:
-                result[elem] = count
-        return result
-
-    def __and__(self, other):
-        ''' Intersection is the minimum of corresponding counts.
-
-        >>> Counter('abbb') & Counter('bcc')
-        Counter({'b': 1})
-
-        '''
-        if not isinstance(other, Counter):
-            return NotImplemented
-        result = Counter()
-        for elem, count in self.items():
-            other_count = other[elem]
-            newcount = count if count < other_count else other_count
-            if newcount > 0:
-                result[elem] = newcount
-        return result


Test patch: