sort the matrix by the order of the first row

i have a matrix.I want to sort the columns of this matrix to be 1,2,3,4,5.... (note: my real matrix is very big. I gave these matrices as an example)

for example

3 5 4 1 2

0.2 0.5 0.7 0.1 0.9

0.7 0.9 0.4 0.3 0.2

new matrix :

1 2 3 4 5

0.1 0.9 0.2 0.7 0.5

0.3 0.2 0.7 0.4 0.9

can you help me with this?

Thanks, Berfin

Answer 1

[Voss]

A = [ ...
    3        5        4        1        2
    0.2    0.5      0.7     0.1    0.9
    0.7   0.9     0.4      0.3     0.2];

[~,idx] = sort(A(1,:));
B = A(:,idx)

B = 3×5

1.0000 2.0000 3.0000 4.0000 5.0000 0.1000 0.9000 0.2000 0.7000 0.5000 0.3000 0.2000 0.7000 0.4000 0.9000

[Berfin Çetinkaya]

Thank u !

[Voss]

You're welcome!

[Berfin Çetinkaya]

So, can we do the opposite?

For example we have a matrix A matrix

1 2 3 4 5

0.1 0.9 0.2 0.7 0.5

0.3 0.2 0.7 0.4 0.9

and there is one more matrix

3 5 4 1 2 Let's call this matrix B

Can we sort matrix A by B?

3 5 4 1 2

0.2 0.5 0.7 0.1 0.9

0.7 0.9 0.4 0.3 0.2

like this

[Voss]

A = [ ...
    1 2 3 4 5
    0.1 0.9 0.2 0.7 0.5
    0.3 0.2 0.7 0.4 0.9];

B = [3 5 4 1 2];

[~,idx] = ismember(B,A(1,:));

C = A(:,idx)

C = 3×5

3.0000 5.0000 4.0000 1.0000 2.0000 0.2000 0.5000 0.7000 0.1000 0.9000 0.7000 0.9000 0.4000 0.3000 0.2000

[Jadyn]

Hi! This is so helpful--thanks so much! I had a similar question: what if you had a missing column, and you want to skip the missing column?

For example, original matrix:

A = [
    5        4        1        2
    0.5      0.7      0.1     0.9
    0.9      0.4      0.3     0.2];

I want my new matrix to look like this:

1.0000    2.0000    0.0000   4.0000    5.0000
0.1000    0.9000    0.0000   0.7000    0.5000
0.3000    0.2000    0.0000   0.4000    0.9000

(doesn't have to be zeros as long as the column is empty)