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pythonmatrixmatrix-multiplicationsubscript

Scalar multiplication of matrix (int is not subscriptable)

Question: You are given a M∗N matrix, and a variable K, print the resultant matrix after scalar multiplication. Code i have written:

n,m,k=map(int,input().split())
mat1=[]
for i in range(n):
    mat1.append(list(map(int,input().split())))

for i in range(n):
    for j in range(m):
        mat1=mat1[i][j] * k
for i in range(n):
    for j in range(m):
        print(mat1[i][j],end=" ")
    print()

Error:

Traceback (most recent call last):
  File "C:/Users/91934/PycharmProjects/pythonProject/main.py", line 8, in <module>
    mat1=mat1[i][j] * k
TypeError: 'int' object is not subscriptable
Solution

  • You're replacing the list variable mat1 with a number value with this line, resulting in the said error:

    mat1=mat1[i][j] * k

    Instead, you should specify the nested list item that is to be assigned by index:

    mat1[i][k] = mat1[i][j] * k

    or:

    mat1[i][j] *= k