CODEWITHSUNDEEP
pythonlistloops
Jacob Friedman
Jacob Friedman

Reputation: 31

For loop definition of a matrix?

I'm making a replica of minesweeper in pygame, and I am trying to make a matrix to keep track of the bombs, but I do not understand a certain matrix definition that I saw online.

I've seen code online that does the following to define a matrix filled completely with zeroes:

def create_table(n):
    return [[0] * n for i in range(n)]

Where n is the number of rows and columns in the matrix.

I don't understand how [0] * n produces, for example if n=3, [0, 0, 0].

Upvotes: 1

Views: 43

Answers (1)

Faboor
Faboor

Reputation: 1383

[0] * 3 is basically just [0] + [0] + [0]. A similar example that might be clearer:

[1, 2, 3] + [4, 5] == [1, 2, 3, 4, 5]

Depending on how you want your matrix to be laid out (either matrix[row][column] or matrix[column][row]), you have to replace the ns by n_columns and n_rows.

Upvotes: 1

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