filter()

The filter() function returns a filter object that contains values from an iterable. If a function returns True for a given item’s value, that value will be included in the returned object.

Syntax

filter(func_name, iterable)

The func_name is the function to be applied to the iterable and can be a lambda function or the name of any defined function. The iterable contains the items, such as a list, the function will act on.

In the examples below list() is applied to the filter expression to return a new list.

Example

The following example uses filter() to return all the odd values in the nums list:

nums = [33, 99, 63, 29, 25, 96, 61, 25, 22, 89, 90, 90]

def odds_test(n):
    n = True if n % 2 == 1 else False
    return n

print(list(filter(odds_test, nums)))
# Output: [33, 99, 63, 29, 25, 61, 25, 89]

Codebyte Example

filter() can be used to return only the strings that are all lowercase:

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