Answers for "nan string in python"

python convert nan to empty string

# Option 1
df1 = df.replace(np.nan, '', regex=True) # All data frame

# Option 2
df[['column1','column2']] = df[['column1','column2']].fillna('') # Specific columns

Identify Null and NAN python

import pandas as pd
pd.isnull(df.columnName).sum()
pd.notnull(df.columnName).sum()