df.isna().sum(axis=1)
np.count_nonzero(df.isnull().values)
np.count_nonzero(df.isnull()) # also works
df.isna().sum().sum()
import pandas as pd
## df1 as an example data frame
## col1 name of column for which you want to calculate the nan values
sum(pd.isnull(df1['col1']))
df.groupby(['No', 'Name'], dropna=False, as_index=False).size()
df.groupby(['No', 'Name'], dropna=False, as_index=False).size()
df.groupby(['No', 'Name'], dropna=False, as_index=False).size()
df.groupby(['No', 'Name'], dropna=False, as_index=False).size()