all()

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

all(iterable)

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

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

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.