MATLAB black hole variable

Question

Does MATLAB have a "blackhole" or discard variable?

Say I'm doing something like:

[ rows cols ] = size( A ) ;

But I don't want rows to be stored. Is there a "black hole" variable where I can send values to die?

So the assignment would be like

[ BLACKHOLE, cols ] = size( A ) ;

Where BLACKHOLE means throw the value away and don't create a variable for it.

possible duplicate of [How to elegantly ignore some return values of a MATLAB function?](http://stackoverflow.com/questions/747296/how-to-elegantly-ignore-some-return-values-of-a-matlab-function) — gnovice, Mar 23 '11 at 15:21
@gnovice: the search fu is strong with you. I'll leave my answer up for the second part for the moment. — Jonas, Mar 23 '11 at 15:23

Jonas · Accepted Answer · 2011-03-23T15:26:15.237

13

For 2009b or later, there is the tilde sign "~"

[~,cols] = size(A);

Alternatively, in your specific case

cols = size(A,2);

edited Mar 23 '11 at 15:26

answered Mar 23 '11 at 15:19

Jonas

score 1 · Answer 2 · answered Mar 25 '11 at 07:50

1

For compatibility with Matlab versions prior to 2009b you can use the following technique

[cols, cols] = size(A);

answered Mar 25 '11 at 07:50

Darren Rowland

2 Answers2