Introduction of Python all() function

Python all() is another Python built-in function.

As per the Python all() documentation, all() returns True if all elements of the iterable are true (or if the iterable is empty).

Syntax of all() built-in function

all(iterable)

Explanation

all() is function name
iterable could be anything, it could be the list, dictionary, set, tuple, etc.
all() function returns True or False, it means it returns a Boolean value.

Examples of Python all() function

Let’s understand all() function in Python by taking a few examples

Using all() function with Python list

Below is an example that describes how we can use all() function with Python list.

Python list all () Example

animals = ["Cow", "Elephant", "Lion"]
print("Elements of animals are",animals)
print("type of animals is",type(animals))

tmp= all(animals)
print(tmp)
print("type of tmp is",type(tmp))

Output

Elements of animals are ['Cow', 'Elephant', 'Lion']
type of animals is <class 'list'>
True
type of tmp is <class 'bool'>

Explanation

animals is the list we created. we can check the type of animals by using type function.
we used tmp variable to get the result from all() function.
print the value from tmp which is TRUE, as all the elements are present in list
At last, we can check the type of tmp variable, which is bool.

Python list all() example with one empty element

animals = ["", "Elephant", "Lion"]
print("Elements of animals are",animals)
print("type of animals is",type(animals))

tmp= all(animals)
print(tmp)
print("type of tmp is",type(tmp))

Output

Elements of animals are ['', 'Elephant', 'Lion']
type of animals is <class 'list'>
False
type of tmp is <class 'bool'>

Explanation

In the above example, the first element of animals list is empty (“”) that’s why the output of all() function is False.

Python list all() example with number elements

#Python all() function with list 
dice = [1, 2, 3]
print("Elements of animals are",dice)
print("type of animals is",type(dice))

tmp= all(dice)
print(tmp)
print("type of tmp is",type(tmp))

Output

Elements of animals are [1, 2, 3]
type of animals is <class 'list'>
True
type of tmp is <class 'bool'>

Explanation

Here dice is a list of numbers instead of String. The output is True as all the elements are present and they are non-zero. if any element is 0, then it returns False. see below example.

Python list all() example with 0 element

#Python all() function with list 
dice = [1, 2,0, 3]
print("Elements of animals are",dice)
print("type of animals is",type(dice))

tmp= all(dice)
print(tmp)
print("type of tmp is",type(tmp))

Output

Elements of animals are [1, 2, 3]
type of animals is <class 'list'>
False
type of tmp is <class 'bool'>

Explanation

Here the output is False as one number is 0, Its important point to understand, if all the numbers are non-zero then all() function will return True. If any number in the iterable is 0, then the output is False.

Using all() with Python tuple

Below is examples of all() function in Python with Python tuple.

Example of Python all() with Python tuple

#Python all() function with tuple 
animals = ("Cow", "Elephant", "Lion")
print("Elements of animals is",animals)
print("type of animals is",type(animals))

tmp= all(animals)
print(tmp)
print("type of tmp is",type(tmp))

Output

Elements of animals is ('Cow', 'Elephant', 'Lion')
type of animals is <class 'tuple'>
True
type of tmp is <class 'bool'>

Explanation

In the above example, we take same animals iterable but now animals is tuple here as elements of animals are started with round brackets( python tuples started with round brackets()).

As we have checked the type of animals using type function. Rest examples and uses cases of all function with Python tuple are same as we discussed in Python list.

Python all() function with set

Let’s see how all() function works in Python with set.

Example of Python set with all() function

#Python all() function with set 
animals = {"Cow", "Elephant", "Lion"}
print("Elements of animals is",animals)
print("type of animals is",type(animals))

tmp= all(animals)
print(tmp)
print("type of tmp is",type(tmp))

Output

Elements of animals is {'Cow', 'Lion', 'Elephant'}
type of animals is <class 'set'>
True
type of tmp is <class 'bool'>

Using all() function with Python dictionary

Python dictionary is key-value pairs. below example will show how we can use function all() built-in function with Python dictionary.

Example of Python dictionary with all() function

#Python all() function with dictionary 
alphabets = {1:"one",
             2:"two",
             3:"three"}
print("Elements of animals is",alphabets)
print("type of animals is",type(alphabets))

tmp= all(alphabets)
print(tmp)

print ("*****************")
meanings = {0:False,
              1:True}

print("Elements of meanings is",meanings)
tmp2= all(meanings)
print(tmp2)

Output

Elements of animals is {1: 'one', 2: 'two', 3: 'three'}
type of animals is <class 'dict'>
True
*****************
Elements of meanings is {0: False, 1: True}
False

Explanation

Here alphabets is python dictionary, all functions return True as all key-value pairs are present and non zero.
In the same example, we have another meanings dictionary. In this dictionary, we have two key-value pairs, 0 and 1. 0 means False, and 1 means True. so all() output will be False because there is one 0 key present.

In Python dictionary, if any key is 0 then all() function will return False

Python all() function on Empty Iterable

If iterable (list, tuple, set, dictionary etc ) is empty then all() function will return True

Example of all() function with empty iterable

#Python all() function with empty iterable 
ilist = list() # = ilist = []
ituple=tuple()  # ituple=()
iset=set()
idict=dict() # idict={}


tmp1= all(ilist)
tmp2= all(ituple)
tmp3= all(iset)
tmp4= all(idict)

print(tmp1)
print(tmp2)
print(tmp3)
print(tmp4)

Output

True
True
True
True

Explanation

we have created an empty list, empty tuple, empty set, empty dictionary. all() function will return True for all empty iterable.