Finding exact rank of a matrix element

Hello:

I have two matrices A and B. I am attaching some parts of original matrices. My question is: how to find elements of matrix B, in column 2 of A to get the corresponding values in column 1 of A?

[madhan ravi]

can you describe the pattern? 3,4,1,2,5??

[Poulomi Ganguli]

yes the desired output is:

61380    3
61480    4
61180    1
61280    2
61580    5

[Guillaume]

1) Please use valid matlab syntax to create your example, so we don't spend time wondering what the matrices actually are. I suspect, but it's not obvious that:

A = [1    61180
     2    61280
     3    61380
     4    61480
     5    61580];
 
B = [61380
     61480
     61180
     61280
     61580];

It also makes it easy for us to copy/paste directly into matlab. Any complication you introduce make it less likely for you to get an answer.

2) What do you call the rank of an element? And which elements are you talking about?

Is your question actually: How do I look up the elements of vector B in column 2 of A to get the corresponding values in column 1 of A?

[Poulomi Ganguli]

Sorry, yes, it is exactly same as in your explanation in comment (2). To look up the elements of vector B in column 2 of A to get the corresponding values in column 1 of A. But A and B are dismilar in size, dimension of B is 516x1 and A is 241x2. Thanks

Answer 1

[Guillaume]

look up the elements of vector B in column 2 of A to get the corresponding values in column 1 of A. But A and B are dismilar in size, dimension of B is 516x1 and A is 241x2

In that case,

[found, where] = ismember(B, A(:, 2));
assert(all(found), 'Some elements of B were not found in A');
B(:, 2) = A(where, 1);

[Poulomi Ganguli]

Exactly, what I wanted; you saved my life.