pd.isnull( code example

Example 1: isnull().mean() python

df.isnull()
#Mask all values that are NaN as True
df.isnull().mean()
#compute the mean of Boolean mask (True evaluates as 1 and False as 0)
df.isnull().mean().sort_values(ascending = False)
#sort the resulting series by column names descending

Example 2: pandas isnull

df.isnull().sum()