pydata/pandas — pull request #5438 by danielballan (2013-11-05 03:27:15+00:00)
Title: WIP: pd.to-timedelta handling missing data

Following @jreback's suggestion in #5437, this does not break any tests, but it changes the datatype to object:

In [1]: Series(['00:00:01', pd.NaT]).apply(pd.to_timedelta)
Out[1]:
0 1000000000 nanoseconds
1 -9223372036854775808
dtype: object