Python pandas cell comma separated list keep only dublicates-CodePudding

import pandas as pd

# Source data
df = pd.DataFrame( data={'A': ['aaa, aaa, aaa', 'aaa, aaa, bbb', 'bbb, aaa, aaa', 'aaa, bbb, ccc'],'B': [ '1', '1', '1', '1']})

for row in df.iterrows():
    df['A'] = df['A']df['A'].duplicated()].unique()

Result:

ValueError: Length of values (100) does not match length of index (1254)

I would like to show duplicated values:

df_2 = pd.DataFrame( data={'A': [ 'aaa', 'aaa', 'aaa', ''],'B': [ '1', '1', '1', '1']})

CodePudding user response：

Use collections.Counter to count and filter the duplicates:

from collections import Counter
df["A"] = [ ",".join(k for k, v in Counter(ai.split(", ")).items() if v > 1) for ai in df["A"]]
print(df)

Output

     A  B
0  aaa  1
1  aaa  1
2  aaa  1
3       1