How to Zip Two Lists in Python: Simple Guide

You can combine two lists element-wise in Python using the zip() function. It pairs elements from each list into tuples, stopping at the shortest list length.

Syntax

The zip() function takes two or more iterables (like lists) and returns an iterator of tuples. Each tuple contains one element from each iterable at the same position.

Basic syntax:

• zip(list1, list2): Combines elements from list1 and list2.
• The result is an iterator, so you often convert it to a list with list(zip(...)) to see all pairs.

python

zipped = zip(list1, list2)
result = list(zipped)

Example

This example shows how to zip two lists of names and ages into pairs.

python

names = ['Alice', 'Bob', 'Charlie']
ages = [25, 30, 35]
zipped_lists = list(zip(names, ages))
print(zipped_lists)

Output

[('Alice', 25), ('Bob', 30), ('Charlie', 35)]

Common Pitfalls

One common mistake is expecting zip() to handle lists of different lengths by filling missing values. Instead, zip() stops at the shortest list length.

Also, remember that zip() returns an iterator, so you need to convert it to a list or loop over it to see the pairs.

python

list1 = [1, 2, 3]
list2 = ['a', 'b']

# Wrong: expecting all elements paired
print(list(zip(list1, list2)))  # Output: [(1, 'a'), (2, 'b')] - stops at shortest list

# Right: use itertools.zip_longest to fill missing values
from itertools import zip_longest
print(list(zip_longest(list1, list2, fillvalue='missing')))

Output

[(1, 'a'), (2, 'b')]
[(1, 'a'), (2, 'b'), (3, 'missing')]

Quick Reference

Remember these points when using zip():

• Pairs elements by position from each list.
• Stops at the shortest list length.
• Returns an iterator, convert to list to view all pairs.
• Use itertools.zip_longest() to handle uneven lists.

Key Takeaways

Use zip() to pair elements from two lists by their positions.

zip() stops at the shortest list length, so extra elements are ignored.

Convert the zip() result to a list to see all pairs at once.

For lists of different lengths, use itertools.zip_longest() to fill missing values.

Remember zip() returns an iterator, not a list.