Skip to content

How to use Python filter()

Python provides 3 useful global functions we can use to work with collections: map(), filter() and reduce().

Tip: sometimes list comprehensions make more sense and are generally considered more pythonic

filter() takes an iterable and returns a filter object, which is another iterable, but without some of the original items.

You do so by returning True or False from the filtering function:

numbers = [1, 2, 3]

def isEven(n):
    return n % 2 == 0

result = filter(isEven, numbers)

print(list(result)) # [2]

You can use a lambda function to make the code more concise:

numbers = [1, 2, 3]

result = filter(lambda n: n % 2 == 0, numbers)

print(list(result)) # [2]

→ Here's my latest YouTube video

→ Get my Python Handbook
→ Get my Python Handbook

→ I wrote 17 books to help you become a better developer, download them all at $0 cost by joining my newsletter

JOIN MY CODING BOOTCAMP, an amazing cohort course that will be a huge step up in your coding career - covering React, Next.js - next edition February 2025

Bootcamp 2025

Join the waiting list