在重复键上添加计数编号以进行合并

Question

我创建了一个合并密钥。不幸的是，有一些重复的密钥。但是我需要保留这些行。我在想，对于每组重复键，我都可以将计数1、2、3等添加到每个重复键中，以使它们唯一。

可以推荐一个命令或方法吗？非常感谢。

这些实际上是我真正坚持如何进行操作之前的代码：

#creating a key variable for merging
df['dfkey'] = df['ColA'].map(str) + ' ' + df['ColB'].map(str) + ' ' + df['ColC'].map(str)    #creating the key
df['dfkeycount'] = df.groupby('dfkey')['dfkey'].transform('count')                           #counting the freq of each dfkey ---> to know if they are unique
df['dfkeycountcat'] = df.groupby(['dfkey','Category'])['dfkey'].transform('count')           #to count the freq of each dfkey per Category Note: Later, will divide the dataset into Category. Then will merge them side by side (one variable will be renamed based on the category name).

dataunique = df.loc[df['dfkeycountcat'] == 1]                                                #created this subset for those with clean keys. I am actually successful with the merging if only within this dataset.
dataduplicate = df.loc[df['dfkeycountcat'] > 1]                                              #this is the dataset that I want to apply the code for adding a sequence number at the end of the key.                                             

Answer 1

非常感谢您的答复。能够使用cumcount ...

df['dfkeynew'] = df['dfkey'].map(str) + df.groupby('dfkey').cumcount().map(str)
df['dfkeycountnew'] = df.groupby('dfkeynew')['dfkeynew'].transform('count')   

df['dfkeycountnew'].value_counts()

它们现在都是独一无二的。