freeCodeCamp/guide/english/python/all-iterable/index.md

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Python All Iterable

all() is a built-in function in Python 3 (and Python 2 since version 2.5), to check if all items of an iterable are True. It takes one argument, iterable.

Argument

iterable

The iterable argument is the collection whose entries are to be checked. It can be a list, str, dict, tuple, etc.

Return Value

The return value is a Boolean. If and only if all entries of iterable are truthy, it returns True. This function essentially performs a Boolean AND operation over all elements.

If even one of them is not truthy, it returns False.

The all() operation is equivalent to (not internally implemented exactly like this)

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

Code Sample

print(all([])) #=> True  # Because an empty iterable has no non-truthy elements
print(all([6, 7])) #=> True
print(all([6, 7, None])) #=> False  # Because it has None
print(all([0, 6, 7])) #=> False  # Because it has zero
print(all([9, 8, [1, 2]])) #=> True
print(all([9, 8, []])) #=> False  # Because it has []
print(all([9, 8, [1, 2, []]])) #=> True
print(all([9, 8, {}])) #=> False  # Because it has {}
print(all([9, 8, {'engine': 'Gcloud'}])) #=> True

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