Python | List Initialization with alternate 0s and 1s
The initialization of list with a single number is a generic problem whose solution has been dealt many number of times. But sometimes we require to initialize the list with elements alternatively repeating K no. of times. This has use cases in M.L or A.I algorithms which require presetting of data in lists. Let’s discuss certain ways in which this problem is solved.
Method #1 : Using list comprehension
In this method, we insert elements in the list alternatively for the specific number of times of each elements’ occurrence. It takes the remainder of sum of counts of both occurrences of elements with particular occurrence of element for cycle computation.
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# Python3 code to demonstrate # to perform cyclic initialization# using list comprehension # count of 1 count_1 = 4 # count of 0count_0 = 3 # total length of list size = 14 # initializing list cyclically# using list comprehensiontest_list = [ 1 if i % (count_1 + count_0) < count_1 else 0 for i in range(size) ] # printing list after changeprint ("The list after initializing : " + str(test_list)) |
The list after initializing : [1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0]
Method #2 : Using itertools.cycle() + itertools.islice()
This is the most pythonic way in which we can perform the cyclic initialization. Slice each of the part of list into the allotted element size in a cyclic manner using cycle function.
# Python3 code to demonstrate # to perform cyclic initialization# using itertools.cycle() + itertools.islice()import itertools # count of 1 count_1 = 4 # count of 0count_0 = 3 # total length of list size = 16 # getting patternpattern = [1] * count_1 + [0] * count_0 # initializing list cyclically# using itertools.cycle() + itertools.islice()test_list = list(itertools.islice(itertools.cycle(pattern), size)) # printing list after changeprint ("The list after initializing : " + str(test_list)) |
The list after initializing : [1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 1]
