CODEWITHSUNDEEP
pythonpandasdataframeduplicatesrunning-count
J. Williams
J. Williams

Reputation: 135

Count duplicate rows and fill in column

I have created a DataFrame, and now need to count each duplicate row (by for example df['Gender']. Suppose Gender 'Male' occurs twice and Female three times, I need this column to be made:

Gender   Occurrence
Male     1
Male     2
Female   1
Female   2
Female   3

Is there a way to do this with Pandas?

Upvotes: 4

Views: 2950

Answers (1)

gereleth
gereleth

Reputation: 2482

Use the cumcount method after grouping by Gender:

df = pd.DataFrame({'Gender':['Male','Male','Female','Female','Female']})   
df['Occurrence'] = df.groupby('Gender').cumcount() + 1
print(df)

   Gender  Occurrence
0    Male           1
1    Male           2
2  Female           1
3  Female           2
4  Female           3

Counts start with 0 so I added a + 1 there.

Upvotes: 8

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