将字符串添加到两列dataframe内的重复字符串

import pandas as pd

data = {'Column1': ['abc', 'def', 'abc', 'ghi'],
        'Column2': ['xyz', 'abc', 'abc', 'def']}
df = pd.DataFrame(data)

string_to_add = 'new_string'

df['Column1'] = df['Column1'].apply(lambda x: x + string_to_add if df['Column1'].duplicated().any() else x)
df['Column2'] = df['Column2'].apply(lambda x: x + string_to_add if df['Column2'].duplicated().any() else x)

print(df)