Issue 1:
Code Sample, a copy-pastable example if possible

from io import StringIO
import pandas as pd

csv = 'Index,Date\n1,2013-01-01 23:00:00\n2,\n3,2013-01-01 23:00:01'
df = pd.read_csv(StringIO(csv), index_col=0, parse_dates=[1])
pd.qcut(df["Date"], 2)

Problem description

qcut raises a ValueError:

Traceback (most recent call last):
File "mve.py", line 26, in <module>
pd.qcut(df["Date"], 2)
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/reshape/tile.py", line 208, in qcut
dtype=dtype, duplicates=duplicates)
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/reshape/tile.py", line 251, in _bins_to_cuts
dtype=dtype)
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/reshape/tile.py", line 344, in _format_labels
labels = IntervalIndex.from_breaks(breaks, closed=closed)
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/indexes/interval.py", line 370, in from_breaks
name=name, copy=copy)
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/indexes/interval.py", line 411, in from_arrays
copy=copy, verify_integrity=True)
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/indexes/interval.py", line 225, in _simple_new
result._validate()
File "/tmp/test/env/lib/python3.5/site-packages/pandas/core/indexes/interval.py", line 265, in _validate
raise ValueError('missing values must be missing in the same '
ValueError: missing values must be missing in the same location both left and right sides

Expected Output

qcut returning something like

Index
1 (2013-01-01 22:59:59.999999999, 2013-01-01 23:00:01.0
2 NaT
3 (2013-01-01 22:59:59.999999999, 2013-01-01 23:00:01.0

Output of pd.show_versions()

INSTALLED VERSIONS

commit: None

python: 3.5.2.final.0

python-bits: 64

OS: Linux

OS-release: 4.13.0-32-generic

machine: x86_64

processor: x86_64

byteorder: little

LC_ALL: None

LANG: de_DE.UTF-8

LOCALE: de_DE.UTF-8

pandas: 0.22.0

pytest: None

pip: 9.0.1

setuptools: 38.5.1

Cython: None

numpy: 1.14.0

scipy: None

pyarrow: None

xarray: None

IPython: None

sphinx: None

patsy: None

dateutil: 2.6.1

pytz: 2018.3

blosc: None

bottleneck: None

tables: None

numexpr: None

feather: None

matplotlib: None

openpyxl: None

xlrd: None

xlwt: None

xlsxwriter: None

lxml: None

bs4: None

html5lib: None

sqlalchemy: None

pymysql: None

psycopg2: None

jinja2: None

s3fs: None

fastparquet: None

pandas_gbq: None

pandas_datareader: None

Issue 2:
Code Sample, a copy-pastable example if possible

eemeter sample

# Your code here
Going to analyze the sample data set

Running a meter for ABC NATURAL_GAS_CONSUMPTION_SUPPLIED
c:\users\wtran\appdata\local\continuum\anaconda3\lib\site-packages\eemeter\modeling\models\caltrack_daily.py:80: RuntimeWarning: invalid value encountered in maximum
np.maximum(df.tempF - bp, 0),
c:\users\wtran\appdata\local\continuum\anaconda3\lib\site-packages\eemeter\modeling\models\caltrack_daily.py:84: RuntimeWarning: invalid value encountered in maximum
np.maximum(bp - df.tempF, 0),
Failed computing derivative (series=Best-fit cooling coefficient, baseline period)
Failed computing derivative (series=Best-fit cooling coefficient, reporting period)
Normal year savings estimate:
1217.526961
68% confidence interval: (1164.475562, 1270.578359)
Reporting period savings estimate:
1169.700996
68% confidence interval: (1116.730092, 1222.671900)

Running a meter for ABC ELECTRICITY_CONSUMPTION_SUPPLIED
Normal year savings estimate:
10465.511272
68% confidence interval: (10297.508645, 10633.513899)
Reporting period savings estimate:
10393.837948
68% confidence interval: (10226.081027, 10561.594870)

Problem description

I installed Anaconda and am using the Anaconda Prompt to try to run the sample data.

There are error messages appeared below before the see the Normal year savings estimate for GAS Consumption. Is this normal or is there anything that I should be typed in the code before typing the eemeter sample code in the command line?

c:\users\wtran\appdata\local\continuum\anaconda3\lib\site-packages\eemeter\modeling\models\caltrack_daily.py:80: RuntimeWarning: invalid value encountered in maximum

np.maximum(df.tempF - bp, 0),

c:\users\wtran\appdata\local\continuum\anaconda3\lib\site-packages\eemeter\modeling\models\caltrack_daily.py:84: RuntimeWarning: invalid value encountered in maximum

np.maximum(bp - df.tempF, 0),

Failed computing derivative (series=Best-fit cooling coefficient, baseline period)

Failed computing derivative (series=Best-fit cooling coefficient, reporting period)

Normal year savings estimate:

1217.526961

68% confidence interval: (1164.475562, 1270.578359)

Reporting period savings estimate:

1169.700996

68% confidence interval: (1116.730092, 1222.671900)

[this should explain why the current behaviour is a problem and why the expected output is a better solution.]

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https://pandas-docs.github.io/pandas-docs-travis/

If the issue has not been resolved there, go ahead and file it in the issue tracker.

Expected Output

Output of pd.show_versions()

[paste the output of pd.show_versions() here below this line]