Source: 📖 Python Cookbook ch4.12 p131

Looping through items in separate containers

The chain() function from itertools allows you to chain together multiple iterables in order to loop through them in succession. This is a more elegant solution than setting up two for loops, one for each iterable, each of which executes the same process on every item.

from itertools import chain

nums = [1, 2, 3]
letters = ['a', 'b', 'c']

for item in chain(nums, letters):
	print(item)					# 1, 2, 3, a, b, c