MATLAB - Cleanly read variables out of a function possibly using some type of varargout...? - matlab

Question

I have function f1 which must contain subfunctions, so I can't use another script:
function vars = f1()
a = 1;
b = 'hello';
c = {[1 2 3]};
currvars = whos; %all variable info
for k = 1:size(currvars, 1)
eval(['vars.(currvars(k).name) = ' currvars(k).name ';']);
end
end
I call the function in a script, and then I create the variables in the script using genvarname() and eval():
vars = f1();
varnames = genvarname(fieldnames(vars));
for k = 1:size(varnames(:),1) %Creates vars with the struct's fieldnames.
eval([varnames{k} ' = vars.' varnames{k} ';']);
end
clearvars vars varnames
I'd like to fit the variable creation process into a function somehow while reading out all the variables only to the script calling it, but I don't want to assign a hundred different variable names to the output. Does anyone have any advice on how to do this?

Answer 1

DON'T CREATE zillions of automatically named variables. This is foolish and terribly poor programming style. Instead, learn to use arrays. Multidimensional arrays, cell arrays, struct arrays.
Or, do what you have done, and then be forced to find a kludge like you are looking for.
Take your pick. Eval is evil.

Answer 2

You could return a structure with "corrected" fieldnames:
function output = someFunc
vars = f1();
protected = { %# some list of varnames you don't want
};
names = fieldnames(vars);
newnames = genvarname(names, protected);
for k = 1:numel(newnames)
output.(newnames{k}) = vars.(names{k});
end
end
If you then use
output = someFunc;
varnames = fieldnames(output);
for k = 1:numel(fieldnames)
eval([varnames{k} ' = output.' varnames{k} ';']);
end
in the script/function where you want the variable names, you have a relatively clean way of locking everything up in the function someFunc without having to pre-define all output variable names.
You can also do this in one step:
function someFunc2
vars = f1();
protected = { %# some list of varnames you don't want
};
names = fieldnames(vars);
newnames = genvarname(names, protected);
for k = 1:numel(newnames)
assignin('caller', newnames{k}, vars.(names{k}));
end
end
Which means you just call the function
someFunc2;
in your script, and the function then defines and assigns all the variables in the script's workspace.
A tiny step forward, but forward nonetheless :)

Answer 3

CREDIT TO RODY...
#Old semi-"global" variables:
function vars = f1()
a = 1;
b = 'hello';
c = {[1 2 3]};
currvars = whos; %all variable info
for k = 1:size(currvars, 1)
eval(['vars.(currvars(k).name) = ' currvars(k).name ';']);
end
end
#Function to assign variables to the calling script's/function's workspace. Variable names are determined by the single structure's fieldnames:
function setvars(func)
vars = func;
protected = {'If needed, put variable names you do not want here'};
names = fieldnames(vars);
newnames = genvarname(names, protected);
for k = 1:numel(newnames)
assignin('caller', newnames{k}, vars.(names{k}));
end
end
#Script call:
setvars(f1);