How can I count values of a column in a pandas data frame and store the count for each value in new column of that data frame?

Asked May 29 '20 at 09:04

Active May 29 '20 at 12:15

Viewed 28 times

I have a pandas data frame with numbers looking like this:

     a   b   c      
0    2   3   1      
1    1   2   2     
2    1   3   2     
3    2   4   1     
4    2   4   1
5    1   1   3

I want to count each unique value in column "b" and add the count for each value to my data frame in a new column accordingly:

     a   b   c  count_b     
0    2   3   1   2    
1    1   2   2   1  
2    1   3   2   2  
3    2   4   1   2  
4    2   4   1   2
5    1   1   3   1

How can I do this?

edited May 29 '20 at 12:15

asked May 29 '20 at 09:04

Sebastian

`count_b` for `3` shoud be `2` – jezrael May 29 '20 at 09:07
Then use `df['count_b'] = df['b'].map(df['b'].value_counts())` – jezrael May 29 '20 at 09:07
"count_b for 3 shoud be 2" correct - just changed that. – Sebastian May 29 '20 at 12:17
1

@jezrael df.map was actually the missing piece I was looking for - works for me perfectly fine - many thanks! – Sebastian May 29 '20 at 12:18

How can I count values of a column in a pandas data frame and store the count for each value in new column of that data frame?

0 Answers0