[FIXED] Generate a simple id from string

Issue

I have a dataframe where I am trying to generate an id (without the complexity of a hash etc) based on an information from a string. The code is as follows:

df['id'] = df.City.str[:3] + '-' + df.Name.str[:3] +'-' + df.index.astype(str)

City    Name        Id
Paris   John        Par-Joh-1
Paris   Paul        Par-Pau-2
Paris   Pierre      Par-Pie-3
Paris   Paula       Par-Pau-4
Rome    Riccardo    Rom-Ric-5
Rome    Jean-Paul   Rom-Jea-6
Rome    Franc       Rom-Fra-7

My problem is that the code does not restart count when the name of the column City changes (see above). How can I adapt the code to reach the desired output (see below)?

City    Name    Id
    Paris   John    Par-Joh-1
    Paris   Paul    Par-Pau-2
    Paris   Pierre  Par-Pie-3
    Paris   Paula   Par-Pau-4
    Rome    Riccardo    Rom-Ric-1
    Rome    Jean-Paul   Rom-Jea-2
    Rome    Franc   Rom-Fra-3

Thank you

Solution

Use GroupBy.cumcount with add 1 and convert to string:

df['id'] = (df.City.str[:3] + '-' + df.Name.str[:3] +'-' + 
            df.groupby('City').cumcount().add(1).astype(str))

Answered By - jezrael