TypeError：尝试获取矩阵中元素的乘积时，无法将序列乘以“列表”类型的非整数

Question

I getting this error when I trying to get the product of the elements in each line and column of matrix.

TypeError: can't multiply sequence by non-int of type 'list'

m[i][j] = m[i] * m[j] <- In this line I try to attribute to this position, the product of the multiplication of elements of i and j in that position,but I getting this problem. Where am I missing?

m = []

number = int(input('Type a number for the limit of matrix:'))

for i in range(number):
    line = []
    for j in range(number):
        line.append(int(input('Type a value for[' + str(i) +','+ str(j) +']:')))
    m.append(line)
for i in range(number):
    for j in range(number):
        m[i][j] = m[i] * m[j]
for i in range(number):
    print(m[i])

Answer 1

Your mistake is that note that m[i] is a list of regular list. We can't just multiply two regular list together.

To work with just regular list, we can access each element, compute the product and just sum them up.

m = []

number = int(input('Type a number for the limit of matrix:'))

for i in range(number):
    line = []
    for j in range(number):
        line.append(int(input('Type a value for[' + str(i) +','+ str(j) +']:')))
    m.append(line)
m2 = [[0]* number for i in range(number)]
for i in range(number):
    for j in range(number):
        m2[i][j] = sum(m[i][k] * m[k][j] for k in range(number))
for i in range(number):
    print(m2[i])

Alternatively, you might like to use more advanced tools such as numpy array.

import numpy as np
m = []

number = int(input('Type a number for the limit of matrix:'))

for i in range(number):
    line = []
    for j in range(number):
        line.append(int(input('Type a value for[' + str(i) +','+ str(j) +']:')))
    m.append(line)
m = np.array(m)
print(np.dot(m, m))