If statement without loop

Hi there are two questions I wish to ask:

First, I would like to use if else statement without the loop. Here is my attempt with the loop:

for k=1:15
    for j=1:10
        if A(j,k) > B(j,1), C(j,k)=0;
        else
           C(j,k)=A(j,k);
        end
    end
end
toc;

This took some computation time but I wish to cutdown the time. I attempt to use:

TR1_Ge70(TR>TR_Ge&)=0;

However, the matrix dimension is incorrect. Here is the example:

Matrix A Matrix B Matrix C

1 2 3 4 5 3 1 2 0 0 0

1 2 3 4 5 2 1 0 0 0 0

1 2 3 4 5 1 0 0 0 0 0

1 2 3 4 5 5 1 2 3 4 0

The second question will be bit massive and I fail to write one. I have a matrix A, let say 3 by 3. I also have matrix B, let say 3 by 3 as well. I wish to multiple the first column of matrix A with the entire matrix B, and the scond column and etc. For example:

Matrix A Matrix B Outcome using first column A: Outcome using second column B:

1 2 2 2 2 1 2 2 1 4 4 2

3 3 2 3 3 2 9 9 6 9 9 6

4 2 3 1 2 1 4 8 4 2 4 2

Based on this, I will get three set outcomes. However, it's seem like I cannot write the code and give me three different outcomes directly. The only way that I think is that I have to maintain only single column of Matrix A, and change it every time in order to get three different outcomes. Is it a quick way to do this? Thank you so much for the help!

[DGM]

What version are you using?

[Hokkien]

Hi I'm using Matlab R2020b

Answer 1

[Stephen23]

A = repmat(1:5,4,1)

A = 4×5

1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5

B = [3;2;1;5]

B = 4×1

3 2 1 5

C = A;
C((1:5)>=B) = 0

C = 4×5

1 2 0 0 0 1 0 0 0 0 0 0 0 0 0 1 2 3 4 0

[Hokkien]

Thank you so much! I understand now!

Answer 2

[David Hill]

TR1_Ge70(TR1>TR1_Ge70(:,1))=0;
for k=1:size(A,2)
  C(:,:,k)=A(:,k).*B;
end

[Hokkien]

Hi Thank you so much, unfornutately I still have dimension problem. I'm sorry if my question is not clear. I have re-edit it with the example:

Matrix A Matrix B Matrix C

1 2 3 4 5 3 1 2 0 0 0

1 2 3 4 5 2 1 0 0 0 0

1 2 3 4 5 1 0 0 0 0 0

1 2 3 4 5 5 1 2 3 4 0

Thank you!