input a 2d array when number of rows and columns are not known in python code example

Example 1: scanning 2d array in python

If you want to take n lines of input where each line contains m space separated integers like:

1 2 3
4 5 6 
7 8 9 

a=[] // declaration 
for i in range(0,n):   //where n is the no. of lines you want 
 a.append([int(j) for j in input().split()])  // for taking m space separated integers as input

Example 2: how to input 2-d array in python

matrix = [input().split() for i in range(no_of_rows)] # if only row is given and the number of coloumn has to be decide by user
matrix= [[input() for j in range(no_of_cols)] for i in range(no_of_rows)] # if both row and coloumn has been taken as input from user