pandas count values including nan code example

Example 1: 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 2: relativefrequencies of the unique values pandas

df.value_counts(normalize=True)