how to check if a column is null in pandas code example

Example 1: find nan value in dataframe python

# to mark NaN column as True
df['your column name'].isnull()

Example 2: python if column is null then

df['real_lastName'] = np.where(df['LastName'].isnull(), df['Middle'], df['LastName'] )

print (df)
  FirstName Middle LastName real_lastName
0       Tom     Ju      NaN            Ju
1      Kity    NaN      Rob           Rob