Check if all elements in List are False in Python

This tutorial will discuss about unique ways to check if all elements in list are false in Python.

Table Of Contents

Technique 1: Using all() method

Using the all() method, we can confirm if a sequence contains all True values. Now, to check if a list has all False values, we can invert the values in List and check if all the values are True or not using all() method. For example, this expression will return ‘True’ if list has all False values,

all(not elem for elem in listOfElements)

Now we can use this to check if all elements in a given list are False or not.

Let’s see the complete example,

# Example 1
listOfElements = [False, False, False, False]

# check if all elements in list are False
if all(not elem for elem in listOfElements):
    print("Yes, All elements in list are False")
else:
    print("No, All elements in list are not False")

# Example 2
listOfElements = [False, True, False, False]

# check if all elements in list are False
if all(not elem for elem in listOfElements):
    print("Yes, All elements in list are False")
else:
    print("No, All elements in list are not False")

Output

Yes, All elements in list are False
No, All elements in list are not False

Technique 2: Using for-loop

Iterate over all the elements of List using a for loop. During iteration, for each element check if it is True or not. As soon as a True element is encountered, break the loop, and mark that list does not have all False values. We have created a function for this,

def is_all_false(listObj):
    '''Returns True if all elements in list are False'''
    result = True
    for elem in listObj:
        if elem:
            result = False
            break
    return result

This function accepts a list as argument, and returns True, if all the elements in this list are False. In this function, we will loop through all the values of list, and will look any non False value.

Let’s see the complete example,

def is_all_false(listObj):
    '''Returns True if all elements in list are False'''
    result = True
    for elem in listObj:
        if elem:
            result = False
            break
    return result

# Example 1
listOfElements = [False, False, False, False]

# check if all elements in list are False
if is_all_false(listOfElements):
    print("Yes, All elements in list are False")
else:
    print("No, All elements in list are not False")

# Example 2
listOfElements = [False, True, False, False]

# check if all elements in list are False
if is_all_false(listOfElements):
    print("Yes, All elements in list are False")
else:
    print("No, All elements in list are not False")

Output

Yes, All elements in list are False
No, All elements in list are not False

Summary

We learned about two different ways to check if a List contains all False values or not. Thanks.