Mean is incorrectly NaN in 'object' DataFrame

[craustin]

from pandas import DataFrame
df = DataFrame({0: [np.nan, 2], 1: [np.nan, 3], 2: [np.nan, 4]}, dtype=object)
df.mean(1)

Expected:
In [33]: df.mean(1)
Out[33]:
0 NaN
1 3.0

Actual:
In [31]: df.mean(1)
Out[31]:
0 NaN
1 NaN

[wesm]

thanks, fixed in the above commit

[james18]

Will this fix apply to the DataFrame.std() function as well?

[wesm]

pretty sure I fixed it and added a test for it in the above commit