Structures

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Charles
Charles on 13 Aug 2011
I have loaded data that contain structures. The structures are of the form I have variable : struct1, struct2, struct3.... I have a 'file' with the list of these variables and want to manipulate the data contained in the structures with a for-loop.
Here is what I did:
for i = 1:numel(files)
data = files(i).data or data{1}.data
some code;
end
I have errors like : Improper index matrix reference and other errors, Cell contents reference from a non-cell array object.
  2 Comments
Charles
Charles on 13 Aug 2011
Thanks, I understand the question is poorly phrased and would make some corrections

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Accepted Answer

Oleg Komarov
Oleg Komarov on 13 Aug 2011
You could have the following structure:
s.myfield = 10;
s.another = 20;
s.hello = 30;
Now suppose you have a list with the fieldnames which also happens to be the function to retrieve them from a structure:
fnames = {'myfield','another','hello'};
(Note that I didn't call the list with the name of the function)
Now you can manipulate the structure using dynamic fieldname indexing:
for n = 1:numel(fnames)
tmp = s.(fnames{n});
% do stuff with tmp or directly with s.(fnames{n})
end
This is a complete reference to manipulate structures: structures
  3 Comments
Oleg Komarov
Oleg Komarov on 14 Aug 2011
How are the variables s and t being created or how are they stored?
If they're stored all in a .mat file then you could:
data = load(myfile.mat)
then
for...
data.(s{n})...
end

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More Answers (1)

Jan
Jan on 13 Aug 2011
I'm not sure if this matchs your question, but similar question appear very often here:
If you use LOAD without catching the output to a variable, the output is directly written to the current workspace. Accessing these variables is probe to errors and often causes troubles, e.g. if a locally used variable is overwritten.
Therefore it is much safer and easier to use LOAD with catching the output:
data = load('File.mat');
field = fieldnames(data);
fprintf(' %s\n', field{:});
disp(data.field{1});
  2 Comments
Jan
Jan on 13 Aug 2011
"I have variable" and "I have a 'file'" is not clear. What is the type andthe contents of "files"? Please post the code completely by editing the original question - *not* as comment or answer. And append a complete copy of the error message, because "and other error" is not exact enough to give an advice.

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