Python | Multiplication till Null value

The prefix array is quite famous in the programming world. This article would discuss a variation of this scheme. This deals with the cumulative list product till a False value, and again starts cumulation of product from occurrence of True value. Let’s discuss certain way in which this can be performed.

Method #1 : Using Naive Method
In the naive method, we just construct the new list comprising of the the product of prev. value of list until False and restarts the procedure once a True value is encountered.





# Python3 code to demonstrate 
# Multiplication till Null value
# using naive method 
# initializing list of lists
test_list = [1, 3, 4, False, 4, 5, False, 7, 8]
# printing original list
print ("The original list is : " + str(test_list))
# Multiplication till Null value
# using naive method
for i in range(1, len(test_list)):
    if test_list[i]: 
        test_list[i] *= test_list[i - 1]
        test_list[i] = 1
# printing result
print ("The computed modified new list : " + str(test_list))


Output :

The original list is : [1, 3, 4, False, 4, 5, False, 7, 8]
The computed modified new list : [1, 3, 12, 1, 4, 20, 1, 7, 56]
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