Count the duplicates in a list of tuples

Question

I have a list of tuples: a = [(1,2),(1,4),(1,2),(6,7),(2,9)] I want to check if one of the individual elements of each tuple matches the same position/element i

Answer 1

use collections library. In the following code val_1, val_2 give you duplicates of each first elements and second elements of the tuples respectively.

import collections
val_1=collections.Counter([x for (x,y) in a])
val_2=collections.Counter([y for (x,y) in a])

>>> print val_1
<<< Counter({1: 3, 2: 1, 6: 1})

This is the number of occurrences of the first element of each tuple

>>> print val_2
<<< Counter({2: 2, 9: 1, 4: 1, 7: 1})

This is the number of occurrences of the second element of each tuple