MATLAB: Anonymous function with variable number of input and output arguments

anonymous functionsvararginvariable inputvariable outputvariadic functions

I am trying to write an anonymous function to generate strings for plotting several variables in multiple figures.
I would like to find an approach that will allow me to implement something like
vtext=@(v) horzcat('X1,',v,'1,''.'',X2,',v,'2,''.'',X3,',v,'3,''.''');
makevtext=@(varargin) vtext(varargin{:});
[atext,btext,ctext]=makevtext('a','b','c');
to produce the strings:
atext = X1,a1,'.',X2,a2,'.',X3,a3,'.'
btext = X1,b1,'.',X2,b2,'.',X3,b3,'.'
ctext = X1,c1,'.',X2,c2,'.',X3,c3,'.'
which I will be using to generate multiple plots of a, b and c later on. I'm using an anonymous function because I'd like to be able to easily change which variables I use this on as I explore my data (e.g., if I instead want to see figures for a, d and e, or for vtext to also include X4 and a/d/e4, etc.), but without having to go through my code and change the arguments of something like 20 plots every time I do this. For context, 1,2,3,4,… are different kinds of distributions (Pareto, exponential, etc.), while a,b,c,d,e,… are histogram counts, PDF, CDF, exceedance, and a number of other derivative functions.
Right now, the above code works if I run atext=makevtext('a'), but [atext,btext]=makevtext('a','b') gives me a "Too many input arguments" error. If I replace line 2 above with (just deleting the "{:}"):
makevtext=@(varargin) vtext(varargin);
then [atext,btext]=makevtext('a','b') gives me a "Too many output arguments" error, but I can also get (incorrectly):
[atext] = makevtext('a')
atext =
1x5 cell array
'X1,' 'a' '1,'.',X2,' 'a' '2,'.''
[abtext] = makevtext('a','b')
atext =
1x7 cell array
'X1,' 'a' 'b' '1,'.',X2,' 'a' 'b' '2,'.''
I know it's supposed to be possible to use both varargin and have multiple outputs in anonymous functions, but can't find any examples using both. Is there actually any way to do this, or do I need to use a different approach entirely?

Best Answer

DC = @(C) deal(C{:});
makevtext = @(varargin) DC(cellfun(@(V) vtext(V), varargin, 'uniform',0 ));