Python Program to Iterate Through Two Lists in Parallel

Example 1: Using zip (Python 3+)

Output

1 a
2 b
3 c

Using zip() method, you can iterate through two lists parallel as shown above.

The loop runs until the shorter list stops (unless other conditions are passed).

Example 2: Using itertools (Python 2+)

Output

1 a
2 b
3 c


1 a
2 b
3 c
4 None

Using the zip_longest() method of itertools module, you can iterate through two parallel lists at the same time. The method lets the loop run until the longest list stops.