How to build python matrix (multidimensional array) based on number of rows and colums received from input

Question

Given rectangular array (matrix) MxN with integer elements. M & N are the number of rows and columns of the rectangular matrix, received from input in one line separated by speces. Next, N lines with M numbers each, separated by a space – the elements of the matrix, integers, not exceeding 100 by absolute value.

For example:

Sample Input:

2 3
1 -2 3
4 5 6

Sample Output:

[[1, -2, 3], [4, 5, 6]]

Code:

cols, rows = [int(i) for i in input().split(" ")] 
l = [[list(map(int, input()))] for j in range(rows)]

With rows its clear, however, I dont know how to control line length, so it be equal to the number, receved from input as cols

Any hints will be appreciated...

Answer 1

First of all based on sample output, I saw that rows and cols should be interchanged and second use split by cols [:cols] as shown in the code below

rows, cols = [int(i) for i in input().split(" ")]
l = [map(int, input().split(" ")[:cols]) for i in range(rows)]

• Murad: thank you, Harshit. Are there a way to control the length of line with input method
• M Z: @Murad I'm not sure if there is a way to limit the length of a user input, as it's basically an interrupt that occurs and the program waits until the user is done typing before running anything else (on that thread/process of course). What Harshit has done with [:cols] is it will cap to the first cols number of integers inputted and will ignore all the rest the user has typed in, so you will result in exactly a row x cols matrix.

Answer 2

Well you can try taking input with a loop and breaking it when you receive empty string in python3.

lis = []
val = [map(int, input().split(" ")]
lis.append(val)
while val != "":
 val = [map(int, input().split(" ")]
 lis.append(val)

There you have it. A matrix without predefined rows and columns.