Python | Test for False list

Last Updated : 04 Jan, 2019

Sometimes, we need to check if a list is completely True of False, these occurrences come more often in testing purposes after the development phase. Hence, having a knowledge of all this is necessary and useful. Lets discuss certain ways in which this can be performed.

Method #1 : Naive Method
In the naive method, we just run a loop from beg to end of list and check manually for each value. This is the most basic way to perform this particular task.

# Python3 code to demonstrate 
# to check for False list 
# using naive method
  
# initializing list  
test_list = [False, False, False, False]
  
# printing original list
print ("The original list is : " + str(test_list))
  
flag = 0
  
# using naive method 
# to check for False list 
for i in test_list :
    if i == True :
        flag = 1
        break
  
# printing result
print ("Is List completely false ? : " +  str(bool(not flag)))

Output:

The original list is : [False, False, False, False]
Is List completely false ? : True

Method #2 : Using all()
This function tests each value to be False and if yes, returns boolean True, else returns false. The list iteration is done using list comprehension.

# Python3 code to demonstrate 
# to check for False list 
# using all()
  
# initializing list  
test_list = [False, False, False, False]
  
# printing original list
print ("The original list is : " + str(test_list))
  
flag = 0
  
# using all()
# to check for False list 
res = all(not i for i in test_list)
  
# printing result
print ("Is List completely false ? : " +  str(res))

Output:

The original list is : [False, False, False, False]
Is List completely false ? : True

Method #3 : Using any()
This function tests for any one of the True value, if found returns True, else returns False value. Negation of this function is used as the result.

# Python3 code to demonstrate 
# to check for False list 
# using any()
  
# initializing list  
test_list = [False, False, False, False]
  
# printing original list
print ("The original list is : " + str(test_list))
  
# using any()
# to check for False list 
res = not any(test_list)
  
# printing result
print ("Is List completely false ? : " +  str(res))

Output:

The original list is : [False, False, False, False]
Is List completely false ? : True

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