In Python, filter() is a built-in function that applies a given function to each element of an iterable and returns a new iterable containing only the elements that satisfy the condition.

Function Syntax

filter(function, iterable)

Parameters:

  • function: A specified function that takes one parameter and returns a boolean value.

    This function determines whether each element in the iterable meets the condition. If the function returns True, the element is included in the iterable returned by filter(); if it returns False, the element is excluded.

  • iterable: An iterable object such as a list, tuple, or set.

filter() returns an iterable object containing only the elements that satisfy the condition.

filter() Function Examples

Suppose we need to filter even numbers from a list. We can use the filter() function:

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

def is_even(number):
    return number % 2 == 0

even_numbers = list(filter(is_even, numbers))

print(even_numbers)  # Output: [2, 4, 6, 8, 10]