How to change a single element in a matrix intialized by list of list in python?

Asked Apr 12 '20 at 13:56

Active Apr 12 '20 at 13:56

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First I initialized a matrix using list of list with one in every element I tried changing this first element in the matrix by assigning it to 2

chessboard=[[1]*8]*8
chessboard[0][0] = 2
for r in chessboard:
  print(r)

The output what i get

[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]
[2, 1, 1, 1, 1, 1, 1, 1]

what I actually expect is

[2, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]
[1, 1, 1, 1, 1, 1, 1, 1]

Can anyone help please

asked Apr 12 '20 at 13:56

Sai Krishna

`chessboard = [[2] + [1] * 7] * 8` – RoadRunner Apr 12 '20 at 14:00
You added the same reference 8 times. you need to create individual lists: `chessboard=[[1 for _ in range(8)] for _ in range(8)]` – Patrick Artner Apr 12 '20 at 14:00
@RoadRunner - superp - now you only have the 1s as "same reference" ? or does the concattenation change that? – Patrick Artner Apr 12 '20 at 14:01

How to change a single element in a matrix intialized by list of list in python?

0 Answers0