NameError: name 'df' is not defined

I don't know why it shows an error every time! I already tried writing def but still the same. Then I remove the last line of my code-df but cannot find a solution.

def cleanTxt(df):      df = re.sub(r'@[A-Za-z0-9]+', '', df) #Removing mentions      df = re.sub(r'#[A-Za-z0-9]+', '', df)  #Removing hastags      df = re.sub(r'RT[\s]+', '', df)   #Removing RTs      df = re.sub(r'https?:\/\/\S+', '', df) #Removing URLs (generally promotional posts)      return df  df['Reviews'] = df['Reviews'].apply(cleanTxt)  df  

the error is--

---------------------------------------------------------------------------  NameError                                 Traceback (most recent call last)  <ipython-input-4-6be97c2325e4> in <module>()        5     df = re.sub(r'https?:\/\/\S+', '', df) #Removing URLs (generally promotional posts)        6     return df  ----> 7 df['Reviews'] = df['Reviews'].apply(cleanTxt)        8 df    NameError: name 'df' is not defined  

https://stackoverflow.com/questions/66970980/nameerror-name-df-is-not-defined April 06, 2021 at 10:49PM