Is there any way to access a variable whose name is expressed by another string variable?

Is there any way in MATLAB to access a variable whose name is expressed by another string variable?

for example, when

myvar = 10;

string_myvar = "myvar";

were in the workspace and substituting the numerical scalar myvar into another myvar2 as

myvar2 = myvar;

Id’ like to find a way to give the right hand side "as the content of string scalar ‘string_myvar’ ".

[KSSV]

Why it is needed? You can striaght away initialize

string_myvar = 10 ; 

Or you may go ahead with the name

myvar = 10 ; 

as it is.

[Stephen23]

"Is there any way in MATLAB to access a variable whose name is expressed by another string variable?"

Yes, there are ways to do this.

But only if you want to force yourself into writing slow, inefficient, obfuscated, complex, buggy code that is hard to debug:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[Daiki]

@Stephen Cobeldick: the alternative ways in your link are what I wanted. thank you!

[Stephen23]

@Daiki Tashiro: my pleasure! If you want more help/explanation/support, there are plenty of experienced volunteers on this forum who can help with those "alternative ways"... just ask!

[Daiki]

I have a further question. In an originally defined function

function varargout = myfun(varargin)

a vector which defines a set of output variable and their order for varargout as

myargout = ["arg1", "arg2", "arg3"];

With this expression, I intend varargout{1} is for arg1. After some calculation, I substitute function output as

varargout{find(strcmp("arg1",myargout))} = arg1;
varargout{find(strcmp("arg2",myargout))} = arg2;
varargout{find(strcmp("arg3",myargout))} = arg3;

but in this way, I need to modify this substitution part every time the contents of myargout is changed, because (of course) the string "arg1" and a variable name arg1 are not related. For instance, if I change its contents to

myargout = ["arg1", "arg3", "arg4"];

(from "arg2" to "arg3" for the second variable of varargout, and from "arg3" to "arg4" for the third), then I need to change the substitution part as

varargout{find(strcmp("arg1",myargout))} = arg1;
varargout{find(strcmp("arg3",myargout))} = arg3;
varargout{find(strcmp("arg4",myargout))} = arg4;

where statement for arg2 is deleted and arg4 is added. What I want to do is automatize this substitution part, by only changing myargout.

Is there a good way for this?

I thought indexing was difficult to apply.

[Stephen23]

Get rid of FIND: logical indexing is simpler.

The robust and efficient approach would be to put all of the variables into one container array (e.g. structure, cell array, table) and then use ISMEMBER or dynamic fieldnames or something similar to select the ones for the output.

For example:

C = {arg1,arg2,..,argN};
N = {'x1','x2',..,'xN'};
userwants = ["x1","x3"];
[X,Y] = ismember(userwants,N);
assert(all(X),'no match')
varargout = C(Y)

[Daiki]

@Stephen Cobeldick Thank you for the good approach, and it works well !

Answer 1

[Chunru]

myvar = 10;
string_myvar = "myvar2"; 
assignin('base', string_myvar, myvar);
myvar2

myvar2 = 10

[Stephen23]

Or we could show beginners how easy it is to write simpler, neater, more robust, more efficient code:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[darova]

:D