how to place an id to every element in list in python
from collections import defaultdict
omg = ['a', 'b', 'c', 'a', 'b', 1]
d = defaultdict(lambda: len(d)) # late binding allows d not to be defined yet
omg_id = [d[x] for x in omg]
# [0, 1, 2, 0, 1, 3]