MATLAB: Operation on structure fields with common part of the field name

charfieldsMATLABstringsstructures

Hi, I have succesfully imported several mat files into a structure with fields names beginning either by "DUT" or "REF". Now I need to divide all the fileds beginning by "DUT" to the corresponding one beginning by "REF", for example, I want to compute DUT_2/REF_2, DUT_4/REF_4 etc…

Best Answer

S.DUT_2 = 2;
S.REF_2 = 3;
S.DUT_4 = 4;
S.REF_4 = 5;
C = fieldnames(S);
U = unique(regexp(C,'\d+$','once','match'))
F = @(n)S.(['DUT_',n]) ./ S.(['REF_',n]);
Z = cellfun(F,U)

Giving:

Related Solutions

MATLAB: What is the possibly easiest way to convert back and forth between a struct scalar and a struct array

Use struct2cell, cell2struct, and fieldnames, like this:

% scalar data:
S = struct('x',magic(5),'y',ones(5),'z',eye(5));
% scalar -> non-scalar:
C = struct2cell(S);
C = num2cell(cat(3,C{:}));
A = cell2struct(C,fieldnames(S),3);
% non-scalar -> scalar:
C = permute(struct2cell(A),[2,3,1]);
C = num2cell(cell2mat(C),1:2);
Z = cell2struct(C,fieldnames(S),3);

And testing against the outputs from your original code:

>> isequal(A,PointArray)
ans =
     1
>> isequal(Z,PointScalar)
ans =
     1
>> isequal(Z,PointScalarNew)
ans =
     1

MATLAB: Error in using cellfun

This is a limitation of the struct( ) function when fed a cell array. If you examine s you will see it is not what you wanted.

You could do it in two steps

>> s = struct(field1,value1,field2,[],field3,value3,field4,value4);
>> s.(field2) = value2
s = 
  struct with fields:
    f1: [1 2]
    f2: {[1]  [2]  [32]  'text'}
    f3: [3.1416 9.8696]
    f4: [1 2 3]
>> cellfun(@(u) numel(u), value2)
ans =
     1     1     1     4
>> cellfun(@(u) numel(u), s.f2)
ans =
     1     1     1     4

The last one should throw an error because s is not a cell array

>> cellfun(@(u) numel(u.f2), s)
Error using cellfun
Input #2 expected to be a cell array, was struct instead.

Best Answer

Related Solutions

MATLAB: What is the possibly easiest way to convert back and forth between a struct scalar and a struct array

MATLAB: Error in using cellfun

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