CODEWITHSUNDEEP
pythonpandascount
Amit V
Amit V

Reputation: 301

count similar rows in Pandas

I want to count number of similar rows in Pandas dataframe, and add it as a new column of 'count'.

For example:

   A  B  C  D
0  1  1  1  1
1  1  1  0  1
2  1  1  1  0
3  1  1  1  0

Should result in:

   A  B  C  D  count
0  1  1  1  1  1
1  1  1  0  1  1
2  1  1  1  0  2
3  1  1  1  0  2

Upvotes: 0

Views: 147

Answers (1)

mozway
mozway

Reputation: 260420

A simple solution is to groupby on all columns and get the group size:

df['count'] = df.groupby(list(df.columns))['A'].transform('size')

output:

   A  B  C  D  count
0  1  1  1  1      1
1  1  1  0  1      1
2  1  1  1  0      2
3  1  1  1  0      2

input:

df = pd.DataFrame({'A': [1, 1, 1, 1],
                   'B': [1, 1, 1, 1],
                   'C': [1, 0, 1, 1],
                   'D': [1, 1, 0, 0]})

Upvotes: 1

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