check if value is null python code example

Example 1: python - check for null values

df.isnull().sum()

Example 2: python if not null

#variable
var = "hello python"

#check is not null
if var is not NaN:
    print('Var is not null')

Example 3: python null ==

if foo is None:
    ...

Example 4: 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