Sort function indices in regards to the original data?

Using the sort function in descending order results in correctly sorted values, but incorrect indices (in regards to the original data):

[val,idx] = sort([86.9565 69.5652 65.2174 52.1739 43.4783 65.2174 91.3043 60.8696],'descend')

val =

91.3043 86.9565 69.5652 65.2174 65.2174 60.8696 52.1739 43.4783

idx =

7 1 2 3 6 8 4 5

The correct idx should be: 2 3 4 7 8 5 1 6

I should note that I want the idx in regards to the original data, e.g. first element of tre vector is 86.9565, what is the idx of this in the sorted vector. Correct answer would be 2, but Matlab gives the idx in regards to the sorted data.

Is there a way to get the idx in regards to the original data?

Answer 1

[the cyclist]

In response to your comment on my other answer (which I posted before you edited your question), here is how to get what you want:

[val,idx] = sort([86.9565   69.5652   65.2174   52.1739   43.4783   65.2174   91.3043   60.8696],'descend');
[~,idx2] = sort(idx)

idx2 = 1×8

2 3 4 7 8 5 1 6

[Nope]

Perfect, thank you!

[Matt J]

You don't need the overhead of a second sort operation to get the desired idx2. See below.

Answer 2

[Matt J]

[val,is] = sort([86.9565   69.5652   65.2174   52.1739   43.4783   65.2174   91.3043   60.8696],'descend');

idx=1:numel(val);
idx(is)=idx;

val,

val = 1×8

91.3043 86.9565 69.5652 65.2174 65.2174 60.8696 52.1739 43.4783

idx,

idx = 1×8

2 3 4 7 8 5 1 6

Answer 3

[the cyclist]

I'm not sure why you think it should be [2 3 4 7 8 5 1 6].

But, the output is correct.

• The 7th element is the largest
• The 1st element is next largest
• ...
• The 5th element is the smallest

[Nope]

Sorry, the original question needed editing.