How to apply a function to an specific column of all variables?

Question

Larissa Perez 2016-11-17

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评论： Larissa Perez 2016-11-18

Hi everyone! I'm new to Matlab, so I'm sure this is a silly question.

I have about 20 variables, all same size matrix. I would like to turn all the values above 50 or below -50 in the first column into NaN, for all the variables. Can someone help me with that? This is what I have been trying to do:

myvars = who;

for i = 1:length(myvars)

   data = eval(myvars{i});
   shear = data(:,1); 
   shear(shear>50)=NaN;
   shear(shear<-50)=NaN;
   data(:,1) = shear;
   eval(myvars{1}) = data;
end

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KSSV 2016-11-17

You have variables saved in workspace which are matrices and in there in first column you want nan? What problem you are facing now with the above code?

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Answer 1

James Tursa 2016-11-17

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编辑：James Tursa 2016-11-17

在 MATLAB Online 中打开

Try this:

eval([myvars{i} ' = data']);

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Answer 2

Jan 2016-11-17

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Don't do this. It is a bad programming style, because it impedes the debugging and performance. You find many discussions in this forum concerning eval, e.g. http://www.mathworks.com/matlabcentral/answers/194902-how-can-use-a-for-loop-to-name-a-matrix#answer_172980.

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Larissa Perez 2016-11-18

What would be the appropriate way to do that then?

Larissa Perez 2016-11-18

在 MATLAB Online 中打开

I have tried reorganizing my data in 6 structures that I called m1-m6, and tried the following code. Still didn't work, don't know what's wrong :(

location = {'m1','m2','m3','m4','m5','m6'};

for i = 1:6

    fields1=fieldnames(m1);
    fields2=fieldnames(m2);
    fields3=fieldnames(m3);
    fields4=fieldnames(m4);
    fields5=fieldnames(m5);
    fields6=fieldnames(m6);
    fields = {'fields1','fields2','fields3','fields4','fields5','fields6'};
    loop = getfield (location{i},{fields{i}});