How to find least 8 values in a 1xN row matrix with their positions?

I have a row matrix with 94 elements, Ex: A=rand(1,94). Now i would like to find the least 8 values in the matrix 'A' with their positions & I would like to form a matrix with the 'position numbers' of least 8 values in matrix 'A'.

I used "[value,position]=min(A)", by using this i could find one least value and its position stored in value and position respectively. But i want 8 least values and their respective positions. Finally, i would like to form a row matrix (1 X 8) with position numbers of least 8 values of matrix 'A'

[Guillaume]

Is it the least 8 different values, or just the least 8 regardless of if they're equal or not?

[Y L V SANTOSH KUMAR]

least 8 different values will be fine. least 8 regardless if they're equal or not will also be helpful. thank u

Answer 1

[Guillaume]

If it's just least 8 regardless regardless of if they're equal or not, simply use sort and only keep the first 8 results:

A = rand(1, 94);
[Asorted, position] = sort(A);
least8 = Asorted(1:8);
position8 = position(1:8);

If it's the least 8 different values:

A = randi(20, 1, 94);
[Asorted, position] = sort(A);
diffvals = find([1 diff(Asorted)]);
least8 = Asorted(diffvals(1:8));
position8 = position(diffvals(1:8));

[Y L V SANTOSH KUMAR]

Thank u, but if i use sort command my actual position value of the least numbers will be changed from 1 to 8 numbers. i want the exact position numbers without sorting.

[Thorsten]

position8 gives you the position in the original, unsorted array, same as ind in my answer below. If this is not what you want then please give an example.

[Guillaume]

Like every function in matlab sort works on a copy of the original data. It never modifies the input.

If you meant something else, you need to rephrase your comment. My answer will give you the least 8 numbers without modifying the input.

"i want the exact position numbers without sorting". Asking for the least (or most) n anything means that by definition you've assigned an ordering to the set. Finding the order of a set is called sorting. You can't do one without the other.

[Y L V SANTOSH KUMAR]

sorry, i didn't see properly. Its working for me. Thank u very much.

Answer 2

[Thorsten]

[~, ind] = sort(A);
B = ind(1:8)

[Y L V SANTOSH KUMAR]

Thank u so much,its working.