How to replace value of elements from another matrix index while keeping the same original index?

Let say I have this matrix:

STAL = [1 3; 2 7; 3 6; 4 2; 5 2; 6 1; 7 4; 8 7]

where

 STAL(:,1) is the number of users from 1 to 8 and 
 STAL(:,2) is the sector information of each user.

Now after long process of algorithm, we will get the following random-generated vectors, for example:

C(1,:) = [0 4 1 0] and 
D(1,:) = [1 7 0 6]

where the numbers in these vectors are the number of users (from STAL(:,1)) Now, I want to replace the number of users with the sector information that is available in STAL(:,2) and then do some comparison.

I tried the following:

New_C = STAL(C,2) but it will not work because it is randomly generated and there is zeros in this vector.

Then I tried the following:

x1 = find(C(1,:)~=0);
value1 = C(1,x1);
New_C (1,1:length(STAL(value1,2))) =STAL(value1,2);
New_C = [2 3 0 0]

However, the problem here is the index of C is different than New_C since I am going to do a comparison between C and D and based on this I am going to delete one of the elements of the original C

For example:

if any(New_C(1,:)==2) && any (New_D(1,:)==4)

then I want to delete the element and replace it with zero of vector C when its sector ( STAL(:,2)) equal to 2

C(1,find(New_C(1,:)==3))=0

but it will not work since the index of C is different than New_C

The expected answer that I am looking for is:

I want to delete the user number (STAL(:,1)) of C when its sector equal 3

C = [0 4 0 0]

since

New_C(1,3)=3

Thanks, Khalid

[dpb]

How about showing us an array and then the result expected? Maybe you did, but I can't decipher what the right answer is, sorry.

[kadaldu]

Thank you dpb very much for your help.

Using the same example above of array ( STAL):

I am looking to delete (replace with zero) specific value of vector C based on the sector information STAL(:,2)

First, I want to replace all of the values of C to be the sector information of STAL(:,2)

For example, I need

C = [0 4 1 0]

to be

New_C = [0 2 3 0]

based on STAL(:,2)

Then after that I am going to do some comparison process

For example, I want to delete the user number ( STAL(:,1)) of C when its sector equal 3

Then the expected answer will be:

C = [0 4 0 0]

since

New_C(1,3)=3

I hope this is clear and thank you again for your help.

Cheers, Khalid

Answer 1

[Andrei Bobrov]

STAL = [1 3; 2 7; 3 6; 4 2; 5 2; 6 1; 7 4; 8 7];
C = [0 4 1 0];
Tr = 3;

New_C = C;
[lo,ii] = ismember(C(:),STAL(:,1));
New_C(lo) = STAL(ii(lo),2);
C(New_C == 3) = 0;

[kadaldu]

Thank you Andrei Bobrov very much!

That's what I am looking for. I really appreciate your help and time.

Cheers,

Khalid