All() and Any() Functions in Python With Examples

all() and any() are convenient functions for checking the truth of the elements of lists, dictionaries, sets, generator expressions, etc.

Table of Contents

`all()` Function in Python

How the all() function works:

>>> help(all)
Help on built-in function all in module builtins:

all(iterable, /)
    Return True if bool(x) is True for all values x in the iterable.    
    If the iterable is empty, return True.

The logic of this function can be represented by the following example:

def is_all_true(iterable):
    for element in iterable:
        if not element:
            return False
    return True

Examples.

All values are True.

>>> all([True, True])
True
>>> all([1, 2])
True

All values are False.

>>> all([False, False])
False
>>> all([None, {}])
False

Values include both True and False.

>>> all([True, False])
False
>>> this_dict = {"a": 1, "b": 0}
>>> all(this_dict.values())
False

Empty iterable.

>>> all([])
True

`any()` Function in Python

How the any() function works:

>>> help(any)
Help on built-in function any in module builtins:

any(iterable, /)
    Return True if bool(x) is True for any x in the iterable.    
    If the iterable is empty, return False.

The logic of this function can be represented by the following example:

def is_any_true(iterable):
    for element in iterable:
        if element:
            return True
    return False

Examples

All values are True.

>>> any([True, True])
True
>>> any([0.1, 0.2])
True

All values are False.

>>> any([False, False])
False
>>> any([0, 0.0])
False

Values include both True and False.

>>> any([True, False])
True
>>> this_tuple = ("not an empty string", "")
>>> any(this_tuple)
True

Empty iterable.

>>> any([])
False

More Complex Examples

Combined With Other Functions, Generators and Custom Conditions

check if the elements of a list are of a specific type

>>> values = ["a", 1, "b"]
>>> all(isinstance(x, str) for x in values)
False

check if all the values in the list are greater than or equal to a certain number

>>> all(x >= 1 for x in [-1, 0, 1, 2, 3])
False

check if any value in the list is less than or equal to a certain number

>>> any(x <= 0 for x in [-1, 0, 1, 2, 3])
True

check for values starting with a specific letter

>>> all(x.startswith("a") for x in ["a", "b"])
False
>>> any(x.startswith("a") for x in ["a", "b"])
True

check if all values in the list are even; check if any value in the list are odd

 
>>> all(x%2 == 0 for x in [2, 4, 6])
True
>>> any(x%2 == 1 for x in [2, 4, 6])
False

Using `all()` Instead of a Chain of "and" Conditions

You can replace the following code

if condition1 and condition2 and condition3...:
    # do something

with all() function

conditions = (condition1, condition2, condition3, ...)
if all(conditions):
    # do something

Example:

user = {"name": "John", "active": True, "subscribed": True}
# both values are boolean anyway
conditions = (user["active"], user["subscribed"])
if all(conditions):
    # do something

Using `any()` Instead of a Chain of "or" Conditions

You can replace the following code

if condition1 or condition2 or condition3...:
    # do something

with any() function

conditions = (condition1, condition2, condition3, ...)
if any(conditions):
    # do something

Example:

product = {"name": "A", "price": 10, "in_stock": True}
conditions = (
    product["price"] == 0,
    not product["in_stock"]
    )
if any(conditions):
    # do something

Advantages of These Functions

Reliability

Built-in functions are a secure and time-tested solution.

Efficiency

all() stops iterating over the elements at the first False value.

any() stops iterating over the elements at the first True value.

Less code

You can replace a loop that just iterates over elements with these built-in functions.

NB