Python pandas: Need to know how many people have met two criteria

With this data set I want to know the people (id) who have made payments for both types a and b. Want to create a subset of data with the people who have made both a and b payments. (this is just an example set of data, one I'm using is much larger)

I've tried grouping by the id then making subset of data where type.len >= 2. Then tried creating another subset based on conditions df.loc[(df.type == 'a') & (df.type == 'b')]. I thought if I grouped by the id first then ran that df.loc code it would work but it doesn't.

Any help is much appreciated.

Thanks.

https://stackoverflow.com/questions/65838272/python-pandas-need-to-know-how-many-people-have-met-two-criteria January 22, 2021 at 09:48AM