Empty dataframe not equal to another empty dataframe in 0.16.1 (original) (raw)

I searched the issues list for "empty dataframe" but did not find anything matching.

In pandas 0.16.1, the result of adding 2 empty dataframes is not equal to another empty dataframe.

This code, in pandas 0.15.2, does what is expected:

import pandas as pd

pd.show_versions()

df1 = pd.DataFrame()

df2 = pd.DataFrame()

assert df1.equals(df1)

assert df2.equals(df1)

assert (df1+df1).equals(df2)

It fails in 0.16.1.

0.15.2 output:

INSTALLED VERSIONS

commit: None python: 2.7.7.final.0 python-bits: 64 OS: Windows OS-release: 7 machine: AMD64 processor: Intel64 Family 6 Model 26 Stepping 5, GenuineIntel byteorder: little LC_ALL: None LANG: en_GB

pandas: 0.15.2 nose: 1.3.6 Cython: 0.21.1 numpy: 1.9.2 scipy: 0.15.1 statsmodels: None IPython: 3.1.0 sphinx: 1.3.1 patsy: 0.3.0 dateutil: 2.4.2 pytz: 2015.4 bottleneck: 0.8.0 tables: 3.1.1 numexpr: 2.3.1 matplotlib: 1.4.0 openpyxl: 1.8.5 xlrd: 0.9.3 xlwt: 0.7.5 xlsxwriter: 0.7.2 lxml: 3.4.0 bs4: 4.3.2 html5lib: 0.999 httplib2: None apiclient: None rpy2: None sqlalchemy: 0.9.7 pymysql: None psycopg2: None

0.16.1 output:

INSTALLED VERSIONS

commit: None python: 2.7.9.final.0 python-bits: 64 OS: Windows OS-release: 7 machine: AMD64 processor: Intel64 Family 6 Model 26 Stepping 5, GenuineIntel byteorder: little LC_ALL: None LANG: None

pandas: 0.16.1 nose: 1.3.6 Cython: 0.22 numpy: 1.9.2 scipy: 0.14.0 statsmodels: 0.6.1 IPython: 3.1.0 sphinx: 1.3.1 patsy: 0.3.0 dateutil: 2.4.2 pytz: 2015.4 bottleneck: 0.8.0 tables: 3.1.1 numexpr: 2.3.1 matplotlib: 1.4.3 openpyxl: None xlrd: 0.9.3 xlwt: None xlsxwriter: 0.7.2 lxml: None bs4: 4.3.2 html5lib: 0.999 httplib2: None apiclient: None sqlalchemy: 1.0.4 pymysql: None psycopg2: None

AssertionError Traceback (most recent call last) c:\test_empty_add_0.16.1.py in () 11 assert df2.equals(df1) 12 ---> 13 assert (df1+df1).equals(df2)

AssertionError: