all()

Returns True if every item in an iterable evaluates to True, otherwise, it returns False.

Syntax

all(iterable)

Example 1

As long as one element in the iterable is False, all() will return False.

my_list = [True, "hello", 17]
print(all(my_list))
# Output: True
my_list = [False, "hello", 17]
print(all(my_list))
# Output: False

Example 2

If the iterable is empty, all() will return True.

my_list = []
print(all(my_list))
# Output: True

The integer 0 evaluates to False; however, all non-zero numbers and strings evaluate to True.

my_list = [4, 3, 2, 1, 0]
print(all(my_list))
# Output: False
my_list = [4, 3, 2, 1, "0"]
print(all(my_list))
# Output: True

Different Types of Iterables

all() can be used on any iterable, such as a list, set, string, dictionary, or tuple.

Lists

my_list = [1, 1, 0, True]
print(all(my_list))
# Output: False

This is False because the integer 0 is False.

Sets

my_set = {1, "False", True, 7}
print(all(my_set))
# Output: True

This is True because strings and non-zero integers are True.

Strings

my_string = "Python is more fun than Javascript"
print(all(my_string))
# Output: True

This is True because strings and non-zero integers are True.

Dictionaries

When all() is used with a dictionary, it evaluates the keys, not the values. That means, even if a value is False, all() will return True if all of the keys evaluate to True.

my_dict = {0: "zero", 1: "one", 2: "two"}
print(all(my_dict))
# Output: False

This is False because the first key, 0, is False.

Tuples

my_tuple = ("Heffalumps", "and", "Woozles")
print(all(my_tuple))
# Output: True

This is True because all items in the tuple are True.

Contributors

Interested in helping build Docs? Read the Contribution Guide or share your thoughts in this feedback form.

Learn Python on Codecademy