Pandas DataFrame计算重复行并填充列

Question

我创建了一个DataFrame,现在需要计算每个重复的行(例如df ['Gender'].假设性别'男性'出现两次而女性出现三次,我需要这个列:

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

有没有办法与熊猫一起做到这一点？

Answer 1

分组后使用cumcount方法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

计数从0开始,所以我在+ 1那里添加了一个.