How to ignore output variables in matlab?

Question

[dummy index] = sort(A);

I want to ignore the first output of sort function and just keep the indices. When I use the above I get a warning in the matlab editor that:

The value assigned to dummy is appears to be unused.

and it suggest to use ~ instead. When I use ~.

[~ index] = sort(A);

I got the following error:

use ~ to ignore a value is not permitted in this context.

Anyone has a solution for this?

I'm confused. There is no use of ~ in your example that you say fails. — user85109
– user85109, Commented Oct 12, 2012 at 2:07

Andreas H. · Accepted Answer · 2012-10-12 02:41:44Z

13

You have to add a comma and separate the output arguments to get ~ to work.

The following works

[dummy index] = sort(A);
[dummy, index] = sort(A);
[~, index] = sort(A);

but

[~ index] = sort(A);

fails.

answered Oct 12, 2012 at 2:41

Andreas H.

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Comments

score 0 · Accepted Answer · 2012-10-12 13:03:29Z

0

It does work, though your question does not even show you using a ~ where you say you get an error.

A = rand(1,5);
[~,ind] = sort(A);

ind
ind =
     3     5     1     2     4

answered Oct 12, 2012 at 2:10

user85109