Python | Count true booleans in a list

Given a list of booleans, write a Python program to find the count of true booleans in the given list.

Examples:

Input : [True, False, True, True, False]
Output : 3

Input : [False, True, False, True]
Output : 2

Method #1 : Using List comprehension

One simple method to count True booleans in a list is using list comprehension.

# Python3 program to count True booleans in a list

def count(lst):

    return sum(bool(x) for x in lst)

# Driver code
lst = [True, False, True, True, False]
print(count(lst))

Output:

3

Method #2 : Using sum()

# Python3 program to count True booleans in a list

def count(lst):

    return sum(lst)

# Driver code
lst = [True, False, True, True, False]
print(count(lst))

Output:

3

A more robust and transparent method to use sum is given below.

def count(lst):

    return sum(1 for x in lst if x)

Method #3 : count() method

# Python3 program to count True booleans in a list

def count(lst):

    return lst.count(True)

# Driver code
lst = [True, False, True, True, False]
print(count(lst))

Output:

3

Method #4 : filter()

# Python3 program to count True booleans in a list

def count(lst):

    return len(list(filter(None, lst)))

# Driver code
lst = [True, False, True, True, False]
print(count(lst))

Output:

3