How to print an error message for matrices of incompatible sizes. Like after testing a compatible matrice of multiplication

Question

I don't know where to input the error code if the matrices are not compatible

# take a 2x2 matrix

A = [ [3, -1], [1,2] ]

# take a 2x2 matrix

B = [ [1,4], [2, -3] ]

result = [ [0,0], [0,0] ]

# iterating by row of A

for i in range(len(A)):

# iterating by column by B

for j in range(len(B[0])):

# iterating by rows of B

for k in range(len(B)):

result[i][j] += A[i][k] * B[k][j]

for r in result:

print(r)

Answer 1

Umar Akorede

# take a 2x2 matrix

A = [ [3, -1], [1,2] ]

# take a 2x2 matrix

B = [ [1,4]]

result = [ [0,0], [0,0] ]

#check length of a and b

if len(A) == 2 and len(B) == 2:
for i in range(len(A)):
for j in range(len(B[0])):
for k in range(len(B)):
result[i][j] += A[i][k] * B[k][j]
for r in result:
print(r)

else:
print("Matrix is not 2x2!")

Here,this will print out an error because B is not 2x2

Answer 2

Umar Akorede

Well you're taking a 2x2 matrix right? Then just do an if statement above the first for loop if the length of matrix a and b is == 2 then run it,else print out an error message

Answer 3

raynard can you kindly copy my code and input what you mean. I don't seem to get it. Thanks

Answer 4

raynard thanks mate!

Answer 5

Umar Akorede no problem🤝