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Passing variable to function with similar name

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Massimo Laspia
Massimo Laspia 2017-7-26
回答： Massimo Laspia 2017-7-26
Hi, I have a workspace with variable EURpippo, EURpluto, EURpaperino. These variables are dynamics, in the sense that they can change in number and second part of the name. Is it possible to create a function that: 1) read from the workspace EUR*** 2) upload all variable that in the name start with EUR?
Thanks
Regards
Massimo
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Stephen23
Stephen23 2017-7-26
编辑：Stephen23 2017-7-26
"Is it possible to create a function that: 1) read from the workspace EUR*** 2) upload all variable that in the name start with EUR?"
Is it possible? Yes.
Is it a good way to write code? No.
Magically making all variables jump from workspace to another workspace totally defeats the whole point of independent workspaces: the fact that they are independent.
And then there are all the problems with magically creating variables:
https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval
Much better would be to not magically create variables like that. Putting meta-data into the names means that your code is going to be slow and complicated. Remember that meta-data is data, which means that it should be stored in a variable, not in the variable name. Then your code would be simpler and much more efficient.

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回答（3 个）

Guillaume
Guillaume 2017-7-26
Rather than using excel to talk to matlab (through the spreadsheet link), I'd use matlab to pull the data from excel. This would be more flexibe and doesn't require paying for a toolbox.
With what you have now, the best thing to do is to fix the mess created by MLPutRanges to put everything into one variable. This has to be executed as a script (not a function) as it needs access to the main workspace:
varnames = who('EUR*');
varvalues = cellfun(@eval, varnames, 'UniformOutput', false);
varpairs = [varnames, varvalues]';
eur = struct(varpairs{:});
You can then use the eur structure to pass all your variables at once to functions. fieldname(eur) gives you the list of all the fields eur.
Jan
Jan 2017-7-26
编辑：Jan 2017-7-26
Don't do this. To juggle with a pile of variables having a magic key in their name is a really bad idea. Even extracting variables from another workspace magically is a bad programming practice, because it cannot be seen in the source code, where which variable is coming from. Store the data in a struct instead:
EUR.pippo = rand(1,17);
EUR.pluto = 'hello';
EUR.paperino = @myFcn;
Then you can start your code by providing EUR as input argument. This is clean and efficient.
Read Stephen's valuable comment carefully.
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Guillaume
Guillaume 2017-7-26
@Stephen,
Unfortunately, it looks like the variables are created thus by MathWorks' MLPutRanges VBA function from the spreadsheet link toolbox!
Stephen23
Stephen23 2017-7-26
@Guillaume: aaah, thank you. Indeed, that is rather unfortunate.

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Massimo Laspia
Massimo Laspia 2017-7-26
ok thanks, so I should launch scripts from vba, right? This will generate automatically strut eur in matlab main workspace.
Massimo

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