Updating 2D array in python

Question

    size = 10
    table = [[0] * size] * size
    for iter in range(size):
        table[iter][iter] = 9

    for iter in range(size):
        print(table[iter])

I am trying to make all daigonal elements to be 9, but instead it is making all the elements as 9.

You could write this in a more succinct way, `table = 9 * np.eye(10, dtype=int)`. — AboAmmar, May 14 '22 at 15:34

score 1 · Accepted Answer · answered May 14 '22 at 15:21

Try using a nested list comprehension to initialize table:

size = 10
table = [[0 for _ in range(size)] for _ in range(size)]
for i in range(size):
    table[i][i] = 9
for row in table:
  print(row)

Output:

[9, 0, 0, 0, 0, 0, 0, 0, 0, 0]
[0, 9, 0, 0, 0, 0, 0, 0, 0, 0]
[0, 0, 9, 0, 0, 0, 0, 0, 0, 0]
[0, 0, 0, 9, 0, 0, 0, 0, 0, 0]
[0, 0, 0, 0, 9, 0, 0, 0, 0, 0]
[0, 0, 0, 0, 0, 9, 0, 0, 0, 0]
[0, 0, 0, 0, 0, 0, 9, 0, 0, 0]
[0, 0, 0, 0, 0, 0, 0, 9, 0, 0]
[0, 0, 0, 0, 0, 0, 0, 0, 9, 0]
[0, 0, 0, 0, 0, 0, 0, 0, 0, 9]

Updating 2D array in python

1 Answers1