Matrix (list) in python

Question

I want to create a matrix ROW x COLS based on another matrix original size ROW x COLS.

ROWS = len(mat)
COLS = len(mat[0])
    
res = [[0 for i in range(ROWS)] for i in range(COLS)]

The above code doesn't work for the following edge case:

mat = [[3],[4],[5],[5],[3]]

My desired output is:

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

However, what I get is:

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

How can I adapt my code to work with any case? ( I do not want to use numpy or any other libraries)

Stanley · Accepted Answer · 2022-04-26 20:11:19Z

2

Swap the ROWS and COLS like so:

res = [[0 for i in range(COLS)] for i in range(ROWS)]

answered Apr 26, 2022 at 20:11

Stanley

3202 silver badges6 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

not_speshal · Accepted Answer · 2022-04-26 20:11:02Z

1

Try:

>>> [[0 for i in range(len(mat[0]))] for j in range(len(mat))]
[[0], [0], [0], [0], [0]]

Also better to use different loop variables instead of i for both:

answered Apr 26, 2022 at 20:11

not_speshal

23.2k2 gold badges18 silver badges33 bronze badges