On Sun, Sep 13, 2020 at 2:29 AM Saurav Chirania <chirania.sau...@gmail.com> wrote: > > I really like that python's sort method accepts a key function as a > parameter which can be used to specify how elements should be compared. > > Similarly, we could have a "key" argument which specifies how elements > should be counted. Let's say we have a list of a million students. I would > like to do something like: > c = Counter(students, key = lambda student: student.marks) > > which would return a Counter which maps marks to the number of students > with that marks. Let's say 29 students in the list had scored 100 marks, so > one entry in the counter would be key=100, val=29. > > So, why doesn't Counter's constructor support this argument? Are there > other pythonic ways to do this? >
If I'm interpreting this correctly, a comprehension should work for you: c = Counter(student.marks for student in students) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
