pandas count nan per column code example

Example 1: pandas determine percentage of nans in column

>>> flights.isna().mean().round(4) * 100

Example 2: find the number of nan per column pandas

In [1]: s = pd.Series([1,2,3, np.nan, np.nan])

In [4]: s.isna().sum()   # or s.isnull().sum() for older pandas versions
Out[4]: 2

Example 3: count rows with nan pandas

np.count_nonzero(df.isnull().values)   
 np.count_nonzero(df.isnull())           # also works