How do I do multiple assignment in MATLAB?

Question

Here's an example of what I'm looking for:

>> foo = [88, 12];
>> [x, y] = foo;

I'd expect something like this afterwards:

>> x

x =

    88

>> y

y =

    12

But instead I get errors like:

??? Too many output arguments.

I thought deal() might do it, but it seems to only work on cells.

>> [x, y] = deal(foo{:});
??? Cell contents reference from a non-cell array object.

How do I solve my problem? Must I constantly index by 1 and 2 if I want to deal with them separately?

Answer 1

DEAL is really useful, and really confusing. foo needs to be a cell array itself, I believe. The following seems to work in Octave, if I remember correctly it will work in MATLAB as well:

> foo = {88, 12}
foo =

{
  [1,1] =  88
  [1,2] =  12
}

> [x,y] = deal(foo{:})
x =  88
y =  12

Answer 2

What mtrw said. Basically, you want to use deal with a cell array (though deal(88,12) works as well).

Assuming you start with an array foo that is n-by-2, and you want to assign the first column to x and the second to y, you do the following:

foo = [88,12;89,13;90,14];
%# divide the columns of foo into separate cells, i.e. do mat2cell(foo,3,[1,1])
fooCell = mat2cell(foo,size(foo,1),ones(size(foo,2),1));
[x,y] = deal(fooCell{:});

Answer 3

You don't need deal at all (edit: for Matlab 7.0 or later) and, for your example, you don't need mat2cell; you can use num2cell with no other arguments::

foo = [88, 12];
fooCell = num2cell(foo);
[x y]=fooCell{:}

x =

    88


y =

    12

If you want to use deal for some other reason, you can:

foo = [88, 12];
fooCell = num2cell(foo);
[x y]=deal(fooCell{:})

x =

    88


y =

    12