Matrix (Create 2 Matrices and Sum them)

Question

How could I build this matrix without using Random/randit? Then I need to do the function sum element by element, of the first two. The sum shall be settled via written sub-programme for that purpose. This subprogram should receive as parameters only the two input matrices and return the resulting matrix if it is possible to evaluate the sum, or None, if it is not possible. After the return of the subprogram, the main program must display the content of the matrix following the format presented in the matrix construction. If None is returned, the main program should send the message "Cannot add matrices of different dimensions".

#Contrução da Matriz 1 e Matriz 2 - Programa Principal
import random
matriz1 = []
n = int(input("Informe a quantidade de linhas\n da matriz 1:" ))
m = int(input("Informe a quantidade de colunas\n da matriz 1:" ))
for i in range(n):
     matriz1.append([])
     for j in range(m):
        matriz1[i].append(random.randint(0,100))

for i in range(len(matriz1)):
    for j in range(len(matriz1[i])):
        print(matriz1[i][j], end=" ")
    print ("\n")


matriz2 = []
n = int(input("Informe a quantidade de linhas\n da matriz 2:" ))
m = int(input("Informe a quantidade de colunas\n da matriz 2:" ))

for i in range(n):
     matriz2.append([])
     for j in range(m):
        matriz2[i].append(random.randint(0,100))

for i in range(len(matriz2)):
    for j in range(len(matriz2[i])):
        print(matriz2[i][j], end=" ")
    print ("\n")

Answer 1

To add up the matrices can do:

def somarMatrizes(matriz1, matriz2):
    if(len(matriz1) != len(matriz2) or len(matriz1[0]) != len(matriz2[0])):
        return None
    result = []
    for i in range(len(matriz1)):   
        result.append([])
        for j in range(len(matriz1[0])):
            result[i].append(matriz1[i][j] + matriz2[i][j])
    return result

To make use of this in the last line of the code can do:

soma = somarMatrizes(matriz1, matriz2) # soma e o nosso retorno, result
if soma is not None:
    for i in soma:
        print(i)
else:
    print('Matrizes devem conter o mesmo numero de linhas e colunas')