Check class of input variables

Question

Ledger Yu 2018-9-12

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418643-check-class-of-input-variables

编辑： Stephen23 2018-9-12

I have a function that requires several input variables:

function output = myFun(A,B,C,D,E,...)
  % code
end

I need to check the class of those inputs and convert all "cell" to "mat" format. Of course I can do something like this:

if iscell(A)
  A = cell2mat(A)
end
if iscell(B)
  B = cell2mat(B)
end
if iscell(C)
  C = cell2mat(C)
end
...

But how do I do that in a for loop?

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Stephen23 2018-9-12

编辑：Stephen23 2018-9-12

"But how do I do that in a for loop?"

Magically accessing variable names in a loop is one way that beginners force themselves into writing slow, complex, buggy code that is hard to debug. read this to know why:

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

The situation is easy to avoid with varargin and indexing.

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Answer 1

Stephen23 2018-9-12

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/418643-check-class-of-input-variables#answer_336456

编辑：Stephen23 2018-9-12

在 MATLAB Online 中打开

Simply using varargin:

function out = myFun(varargin)
idx = cellfun(@iscell,varargin);
varargin(idx) = cellfun(@cell2mat,varargin(idx),'uni',0);
...
end

You can then access the elements of varargin trivially using indexing.

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Ledger Yu 2018-9-12

在 MATLAB Online 中打开

After this, I suppose I should do something like this:

A = varargin{1};
B = varargin{2};
C = varargin{3};
...

or is there an easier way?

Stephen23 2018-9-12

编辑：Stephen23 2018-9-12

在 MATLAB Online 中打开

"After this, I suppose I should do something like this:"

A = varargin{1};
B = varargin{2};
C = varargin{3};

I don't suppose that, but you could if you want to. Personally I would not bother, because all of the data is trivially accessibly using indexing already.

"or is there an easier way?"

No. Read my comment to know why:

https://www.mathworks.com/matlabcentral/answers/418643-check-class-of-input-variables#comment_609338

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