How can I design a Python function to print a matrix with only the forward diagonal elements set to True?

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Chapters
00:00 How Can I Design A Python Function To Print A Matrix With Only The Forward Diagonal Elements Set To
00:42 Answer 1 Score 1
00:53 Accepted Answer Score 1
01:08 Thank you

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Full question
https://stackoverflow.com/questions/6886...

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Tags
#python #arrays #multidimensionalarray

#avk47

ANSWER 1

Score 1

The problem is that the shorthand you're using to create lists actually just creates copies of the same list. You can check this with the id function:

n = 5
dp = [[False]*n]*n
print([id(x) for x in dp])

ACCEPTED ANSWER

Score 1

The reason is that multiplying with * does not create new object, as @TobyPetty mentioned.

The way to fix would be:

def func(n):
    dp = [[[False] for i in range(n)] for x in range(n)]
    for i in range(n):
        dp[i][i] = True
    print(dp)