How to remove unwanted string from column?

Question

One of my columns df["reviews"] has reviews in it but only some reviews end with the string "Was this information helpful?...."
So if my row contains this string, I want to get rid of the last 42 characters [:-42] which includes Was this information helpful?

how can I do this in Pandas
Tried this but it isn't working

def remove_unwanted(a):
    if "Was this information helpful" in a:
        print(a[:-42])   
    else:
        print("False")
        
# column without yes and no in complaint body
df['cleaned_reviews'] = df.apply(lambda row: remove_unwanted(row['reviews']), axis = 1)

Answer 1

试试这个，我想这就是你要找的

df['cleaned_reviews'] = df['reviews'].str.rstrip('Was this information helpful?')