Python – all() function

The Python all() function returns true if all the elements of a given iterable (List, Dictionary, Tuple, set, etc.) are True otherwise it returns False. It also returns True if the iterable object is empty. Sometimes while working on some code if we want to ensure that user has not entered a False value then we use the all() function.

Python all() Function in Python

Syntax: all( iterable )

• Iterable: It is an iterable object such as a dictionary,tuple,list,set,etc.

Returns: boolean

Python all() Function with Example

Python3

print(all([True, True, False]))

Output:

False

Example 1: Working of all() with Lists

Here we are considering list as a iterable.

Python3

# All elements of list are true
l = [4, 5, 1]
print(all(l))

# All elements of list are false
l = [0, 0, False]
print(all(l))

# Some elements of list are
# true while others are false
l = [1, 0, 6, 7, False]
print(all(l))

# Empty List
l = []
print(all(l))

# all() with condition - to check if all elements are greater than 0
l = [1,-3,0,2,4]
print(all(ele > 0 for ele in l))

Output

True
False
False
True
False

Example 2: Working of all() with Tuples

Here we are considering a tuple as a iterable.

Python3

# All elements of tuple are true
t = (2, 4, 6)
print(all(t))

# All elements of tuple are false
t = (0, False, False)
print(all(t))

# Some elements of tuple
# are true while others are false
t = (5, 0, 3, 1, False)
print(all(t))

# Empty tuple
t = ()
print(all(t))

# all() with condition - to check if all elements are even
l = (2,4,6,8,10)
print(all(ele % 2 == 0 for ele in l))

Output

True
False
False
True
True

Example 3: Working of all() with Sets

Here sets are referred to as iterables

Python3

# All elements of set are true
s = {1, 1, 3}
print(all(s))

# All elements of set are false
s = {0, 0, False}
print(all(s))

# Some elements of set
# are true while others are false
s = {1, 2, 0, 8, False}
print(all(s))

# Empty set
s = {}
print(all(s))

# all() with condition - to check if absolute of all elements is greater than 2
l = {-4,-3,6,-5,4}
print(all(abs(ele) > 2 for ele in l))

Output

True
False
False
True
True

Example 4: Working of all() with Dictionaries

Here we are considering dictionaries as iterables.

Python3

# All elements of dictionary are true
d = {1: "Hello", 2: "Hi"}
print(all(d))

# All elements of dictionary are false
d = {0: "Hello", False: "Hi"}
print(all(d))

# Some elements of dictionary
# are true while others are false
d = {0: "Salut", 1: "Hello", 2: "Hi"}
print(all(d))

# Empty dictionary
d = {}
print(all(d))

# all() with condition - to check if all letters of word 'time' are there
l = {"t":1, "i":1, "m":2, "e":0}
print(all(ele > 0 for ele in l.values()))

Output

True
False
False
True
False

Note: In the case of a dictionary if all the keys of the dictionary are true or the dictionary is empty the all() returns True, else it returns False.

Example 5: Working of all() with Strings

Python3

# Non-Empty String
s = "Hi There!"
print(all(s))

# Non-Empty String
s = "000"
print(all(s))

# Empty string
s = ""
print(all(s))

Output

True
True
True