how to return cell array with varargout?

Dear all,

I know the title is not that explicit but I did not find a short way to formulate my question.

Here (MATHWORKS - Simple explanation - how to use varargout) was given an example to use .

I remind here the code suggested:

function varargout = varargoutexample(x)

    % Demonstrates how to use VARAGOUT.  
    % Pass in a vector of values.
    % Note that NARGOUT is the number of output
    % arguments you called the function with.
    
    for ii = 1:nargout  
      varargout{ii} = x.^ii;
    end

How can I change the code so as to get a dynamic cell array as an output.

To be more explicit I imagine something like:

function varargout = varargoutexample(N,x)
    
    for ii = 1:N
      varargout{ii} = x.^ii;
    end

such as when I call the function I have:

% in the shell

my_cell = cell(1,3); % pre-allocation

>> my_cell = varargoutexample(3,2)

my_cell =

1x3 cell array

{[2]} {[4]} {[8]}

And then get easy acces to the elements of my_cell :

my_cell{1} = 2

my_cell{2} = 4

my_cell{3} = 8

When I print the loop I have the expected result:

>> my_cell = varargoutexample(3,2)

ii =

1

varargout =

1×1 cell array

{[2]}

ii =

2

varargout =

1×2 cell array

{[2]} {[4]}

ii =

3

varargout =

1×3 cell array

{[2]} {[4]} {[8]}

But when I call my_cell I only get 2 which corresponds to the first loop result...

I hope I am clear enough.

Thanks a lot in advance!

Best regards,

louis

[Stephen23]

As Adam Danz showed, the solution is to use a comma-separated list on the output:

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/1656435-tutorial-comma-separated-lists-and-how-to-use-them

[Steven Lord]

And the pattern Adam Danz showed in the accepted answer matches the "Function Return Values" section on the first of the pages to which Stephen23 linked.

[Louis Tomczyk]

@Stephen23 thanks for the link, I didn't think about typing such keywords...

Answer 1

[Adam Danz]

myCell = cell(1,3); 
[myCell{:}] = myfunc(__)

[Louis Tomczyk]

such reactivity!

perfect, thanks a lot!

Best,

louis

Answer 2

[Jonas]

if i understand you cirrectly, you want as dynamic output variable varargout, and each of the given should/can be a cell itself

so not this

[a,b,c]=varargoutexampleMultVar(3,2)

a = 2

b = 4

c = 8

but you want a cell

a=varargoutexample(3,2)

a = 1×3 cell array
    {[2]}    {[4]}    {[8]}

function varargout = varargoutexampleMultVar(N,x)
    varargout=cell(1,N);
    for ii = 1:N
      varargout{ii} = x.^ii;
    end
end


function varargout = varargoutexample(N,x)
    for ii = 1:N
      varargout{1}{ii} = x.^ii;
    end
end

[Louis Tomczyk]

Yes you got it right!

You function varargoutexample is working well and I wanted to accept both answers but it seems we cannot...

Ok now I wonder why it has been created like this?

The purpose of variable number of outputs shouldn't be because we might change the number of outputs from time to time?

thanks again.

Best,

louis

[Stephen23]

Note that VARARGOUT does absolutely nothing in the VARARGOUTEXAMPLE function, it can be simply replaced with a normal named output argument:

a = normalexample(3,2)

a = 1×3 cell array
    {[2]}    {[4]}    {[8]}

function out = normalexample(N,x)
out = cell(1,N);
for ii = 1:N
    out{ii} = x.^ii;
end
end

[Louis Tomczyk]

@Stephen23 Yes that was obvious but I still don't understand the idea of needing to put exactly the right number of output arguments, for a function which will return time-varying number of outputs....

Indeed the syntaxt :

[mycell{:}]

is not obvious to me even if I admit I am far from being an expert...