Code Sample, a copy-pastable example if possible

df = pd.DataFrame({
        'dates_1' : pd.date_range(start='2015-01-01', periods=5),
        'dates_2' : pd.date_range(start='2016-01-01', periods=5)
})

df.dates_2 - df.dates_1
df_2 = df.drop(df.index)
df_2.dates_2 - df_2.dates_1

Problem description

Subtracting two empty Series with dtypes of datetime64[ns] causes a TypeError to be thrown.

Expected Output

Would expect the subtraction to return an empty series of timedelta64[ns]. i.e, Series([], dtype: timedelta64[ns])

Output of pd.show_versions()

INSTALLED VERSIONS ------------------ commit: None python: 3.5.2.final.0 python-bits: 64 OS: Windows OS-release: 7 machine: AMD64 processor: Intel64 Family 6 Model 45 Stepping 7, GenuineIntel byteorder: little LC_ALL: None LANG: None pandas: 0.18.1 nose: 1.3.7 pip: 9.0.1 setuptools: 27.2.0 Cython: 0.25.1 numpy: 1.11.1 scipy: 0.18.0 statsmodels: 0.6.1 xarray: None IPython: 5.1.0 sphinx: 1.4.1 patsy: 0.4.1 dateutil: 2.5.3 pytz: 2016.6.1 blosc: None bottleneck: None tables: 3.2.2 numexpr: 2.6.1 matplotlib: 1.5.1 openpyxl: None xlrd: 1.0.0 xlwt: 1.1.2 xlsxwriter: 0.9.2 lxml: None bs4: 4.5.1 html5lib: None httplib2: None apiclient: None sqlalchemy: 1.0.13 pymysql: None psycopg2: None jinja2: 2.8 boto: 2.42.0 pandas_datareader: None

Comment From: jreback

has been fixed in more recent versions (maybe this https://github.com/pandas-dev/pandas/commit/d8cd33b148daba78f1450c19c69cfe4896cfb98c) fixed.

In [1]: df = pd.DataFrame({
   ...:         'dates_1' : pd.date_range(start='2015-01-01', periods=5),
   ...:         'dates_2' : pd.date_range(start='2016-01-01', periods=5)
   ...: })
   ...: 
   ...: df.dates_2 - df.dates_1
   ...: df_2 = df.drop(df.index)
   ...: df_2.dates_2 - df_2.dates_1
   ...: 
Out[1]: Series([], dtype: timedelta64[ns])

In [2]: pd.__version__
Out[2]: '0.19.2'