how to add specific column related to other column in data frame

Asked Mar 22 '20 at 15:29

Active Mar 22 '20 at 15:32

Viewed 32 times

i want to add specific column that related to other column in dataframe

this is my code:

import pandas as pd
import numpy as np

df = pd.DataFrame(
    data={'index': ['1','2','3','4','5','6','7','8','9','10'], 
    'charac' : ['A','A','A','A','A','A','A','B','B','B']})

When it's the same in 'charac', it goes on continuously. but it's different in 'charac', it starts again

like this 'add_col' = [1,2,3,4,5,6,7,1,2,3]

i think it can be work with 'for' but i don't know how to do .... could you tell me the answer ..?

edited Mar 22 '20 at 15:32

DOOM

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asked Mar 22 '20 at 15:29

cookies poo

can you provide us the desirable result (dataframe) ? – dzakyputra Mar 22 '20 at 15:33
What is .. **When it's the same in 'charac', it goes on continuously. but it's different in 'charac', it starts again** – DOOM Mar 22 '20 at 15:34
2

`df['add_col'] = df.groupby('charac').cumcount().add(1)` – Quang Hoang Mar 22 '20 at 15:35
oh my god! Quang Hoang _ thank you so much.... !!!! it works thank you – cookies poo Mar 22 '20 at 15:47

how to add specific column related to other column in data frame

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