ERROR- Too many outputs requested. Most likely cause is missing [] around left hand side that has a comma separated list expansion.

function class = find( name, op, varargin )
list = misc.subclasses( 'bembase' );
%  number of NEEDS agreements with options
n = zeros( size( list ) );
%  add property pairs to option structure
for i = 1 : 2 : length( varargin )
  op.( varargin{ i } ) = varargin{ i + 1 };
end

%  loop through list
for i = 1 : length( list )
  %  classes with name matching NAME
  if strcmp( eval( [ list{ i }, '.name' ] ), name )
    %  get needs of class
    needs = eval( [ list{ i }, '.needs' ] );
    %  loop over NEEDS 
    for j = 1 : length( needs )
      if ischar( needs{ j } )
        needs{ j } = isfield( op,  needs{ j } ) &&  ...
                    ~isempty( op.( needs{ j } ) );
      else
        %  get fieldname of structure
        fname = subsref( fieldnames( needs{ j } ), substruct( '{}', {} ) );
        %  compare with OP entries
        needs{ j } = isfield( op, fname ) &&   ...
                     isequal( op.( fname ), needs{ j }.( fname ) );
      end 
    end
    %  number of agreements
    if all( cell2mat( needs ) ),   n( i ) = numel( needs );  end
  end
end

%  find maximum number of agreements
[ ~, i ] = max( n );  
% return name of class or empty cell if not all options match
if n( i ) == 0,  class = {};  else  class = list{ i };  end

showing error

 Too many outputs requested.  Most likely cause is missing [] around left hand side
 that has a comma separated list expansion.
Error in bembase.find (line 51)
if n( i ) == 0,  class = {};  else  class = list{ i };  end

[Matt J]

OK, so what does the debugger tell you?

[annu dahiya]

same error in the same line.

[Bruno Luong]

what is the size (not length) of list?

[annu dahiya]

its showing

0 0

[Bruno Luong]

That's the source of the problem

list{ i }

is "emptyness", you can't assign nothing to something (class on the LHS).

You might change your test to

if isempty(n) || n( i ) == 0, ...

[annu dahiya]

So what should i do?

[Bruno Luong]

See my post edited

[Steven Lord]

function class = find( name, op, varargin )

I strongly recommend you rename your function. Code that calls find expecting to call the built-in function but instead calls your function are likely to be unhappy.

%  classes with name matching NAME
if strcmp( eval( [ list{ i }, '.name' ] ), name )

Avoid using eval if possible. In this case, if list{i} is an object you can through dynamic field names. [Yes, I know objects aren't struct arrays. The syntax still works.]

I'm not completely sure what your function is trying to do, but I suspect there may be functionality in MATLAB already that you can use to do what you want. [I'm thinking perhaps the functions for working with class metadata or perhaps a digraph to analyze dependencies between objects.] Can you describe in words the purpose of your function to help us determine if I'm right?

Answer 1

[Walter Roberson]

Your n is coming out empty because list is empty. max() of empty returns empty into i . list{i} is empty emptiness, no outputs, so assigning it to something is too many outputs.