In [4]:
import numpy as np
import pandas as pd

dates = pd.date_range('20160101', periods=6)
df = pd.DataFrame(np.arange(24).reshape((6,4)), index=dates, columns=['A', 'B', 'C', 'D'])

df.iloc[0,1] = np.nan
df.iloc[1,2] = np.nan
df


Out[4]:
A B C D
2016-01-01 0 NaN 2.0 3
2016-01-02 4 5.0 NaN 7
2016-01-03 8 9.0 10.0 11
2016-01-04 12 13.0 14.0 15
2016-01-05 16 17.0 18.0 19
2016-01-06 20 21.0 22.0 23

In [6]:
print df.dropna(axis=0, how='any') #any  all


             A     B     C   D
2016-01-03   8   9.0  10.0  11
2016-01-04  12  13.0  14.0  15
2016-01-05  16  17.0  18.0  19
2016-01-06  20  21.0  22.0  23

In [9]:
print(df.fillna(value=0))


             A     B     C   D
2016-01-01   0   0.0   2.0   3
2016-01-02   4   5.0   0.0   7
2016-01-03   8   9.0  10.0  11
2016-01-04  12  13.0  14.0  15
2016-01-05  16  17.0  18.0  19
2016-01-06  20  21.0  22.0  23

In [13]:
print(pd.isnull(df))
print np.any(df.isnull) == True


                A      B      C      D
2016-01-01  False   True  False  False
2016-01-02  False  False   True  False
2016-01-03  False  False  False  False
2016-01-04  False  False  False  False
2016-01-05  False  False  False  False
2016-01-06  False  False  False  False
False