Operation on structure fields with common part of the field name

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...

[Stephen23]

Do all of the DUT fields having a matching REF field (and vice versa) ?

Do you want the fields processed in a particular order ? (if so, what order?)

Note that this would likely be a lot simpler with a non-scalar structure, rather than awkwardly forcing meta-data (i.e. the indexing) into the fieldnames:

https://www.mathworks.com/help/matlab/matlab_prog/access-multiple-elements-of-a-nonscalar-struct-array.html

[Romain Liechti]

Yes, all the DUT have a matching REF. No particular order, the aim at the end is to have a structure of the ratio of DUT/REF with the corresponding name 1, 2 etc.

Yeah I know that's probably not the best way to do it, but I've loaded the data from my folder (all the DUT and REF files) into this structure, with the name of the file as the name of the field.

Any other idea is of course welcome

Answer 1

[Stephen23]

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:

U = 
    '2'
    '4'
Z =
      0.66667
          0.8

[Romain Liechti]

Thanks for answering. I'm not familiar with anonymous function, does this solution could work if the fields of the structure S contains vectors ?

I actually forgot to mention that all of my fields are vectors of measured data of the same length.

[Stephen23]

"does this solution could work if the fields of the structure S contains vectors"

You will need to call cellfun with 'uniformoutput' set to false:

Z = cellfun(F,U, 'uni',false)

Everything else should work without change.

"I'm not familiar with anonymous function,..."

https://www.mathworks.com/help/matlab/matlab_prog/anonymous-functions.html

[Romain Liechti]

Thanks a lot, it works just fine!