How to sort or rearrange a column with respect to the other column?!

Hello Everybody;

wish you are all doing well;

if i have a data of two columns and i want to sort one of the columns in a descending order and also keep the other column fixed and likened with the changed one, how can i do that?! assuming that column 1 is the ID of column two

sample data:

241 5

1245 4

684 4

806 4

674 3

Appreciating your help ;

Answer 1

[Azzi Abdelmalek]

Use sortrows function. For example

A=[241 5;1245  4;684 4;806 4;674 3]
B=sortrows(A,2)

% Or by descending order

B=sortrows(A,-2)

[Mariam Sheha]

thanks for your answer, but that one make it in an ascending order... i want it in a descending order

[Azzi Abdelmalek]

B=flipud(sortrows(A,2))

[Azzi Abdelmalek]

Or

B=sortrows(A,-2)

[Guillaume]

Please, read the documentation of sortrows. You can sort according to whichever column and whichever direction you wish.

The documentation contains lots of useful information!

[Mariam Sheha]

thanks it is brilliant :)

Answer 2

[Shameer Parmar]

Hello Mariam,

For your given sample data:

 A =

         241           5
        1245           4
         684           4
         806           4
         674           3

use following code:

 A = [241, 5; 1245, 4; 684, 4; 806, 4; 674, 3];
 B(:,1) = sort(A(:,1),'descend');
 for i=1:length(A)
      B(i,2)=A(find(ismember(A(:,1),B(i))),2);
 end
 B

OutPut will be like in '*descending*' order

B =

        1245           4
         806           4
         684           4
         674           3
         241           5

[Mariam Sheha]

thanks for your answer but thats also arrange it in ascending order, i need it in a descending order that i had already made but i want to flip data to be in the descending order..

[Guillaume]

Both sortrows and sort allows you to specify the direction. I recommend using sortrows as it's more suited to what you want.

If you were to use sort, I would use the 2nd return value to reorder the other columns rather than a loop and ismember:

[B(:, 1), order] = sort(A(:, 1), 'descend');
B(:, 2) = A(order, 2);

As said, sortrows as per Azzi's answer is better.

[Mariam Sheha]

thanks for your quick answer and recommendation is appreciated :)