MATLAB: Creating a loop to search for matching values in two matrices

loopmultiply cells

I have two csv files. A is 55473 x 10 and B is 484 x 3. I want to create a loop that goes through column 5 in A, and when the value in the cell equals a value in column 1 in B, i want to multiply it by column 2 and column 3 of the same row in B. I want to repeat this for all values in column 5 of A.

Best Answer

You can do it without a for loop

[ii,jj]=ismember(A(:,5),B(:,1));
id=nonzeros(jj);
A(ii,5)=A(ii,5).*B(id,2).*B(id,3);

Related Solutions

MATLAB: Associate index of equal element in two arrays

If I understand your Question correctly, the intersect function will do exactly what you want:

A=[1;3;7;2;5];
B=[5;7;2;1;3];
[C,ia,ib] = intersect(A,B, 'stable')
Result = [C ia ib]
Result =
       1     1     4
       3     2     5
       7     3     2
       2     4     3
       5     5     1

The first column is the element, the second is the index of ‘A’ and the third, of ‘B’.

MATLAB: Match row and column

You can use ismember to generate the logical indices. In the same order as a:

>> idx = ismember(a(:,1:2),b,'rows');
>> a(idx,:)
ans =
    3    7    0
    5   10    0

Or in the same order as b:

>> [~,idx] = ismember(b,a(:,1:2),'rows');
>> a(idx,:)
ans =
    5   10    0
    3    7    0

Best Answer

Related Solutions

MATLAB: Associate index of equal element in two arrays

MATLAB: Match row and column

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