If always splitting on ',' is correct for your data, then your solution is probably fine. You probably want '^foo,' though, otherwise yours includes things wher

If always splitting on ',' is correct for your data, then your solution is probably fine. You probably want '^foo,' though, otherwise yours includes things where 'foo' is just a prefix of the first column value. But CSV permits quoted fields that contain literal ','. So in that case, splitting on ',' would be incorrect.