MATLAB: How to extract data from a cell array which contains structs

cellcell arraysMATLABstructs

Hi all,
I have the following problem: I have a cell array which contains in each cell a certain struct (structs have the same fields but different information). Suppose a certain field contain numbers. I want to create an array from all the numbers of this field from all the structs in the cell array. I can do this with a for loop but I guess there should be a better and a faster way. I tried to do it using 'deal' but failed.
Is there a better way?
Thanks, Alon

Best Answer

Something like this might work for you:
cell2mat(cellfun(@(s)s.field,C,'uni',0))
it assumes that the data is able to be concatenated into one array, and that the structures are scalar. You will need to use the correct fieldname, and orient the input cell array and its contents to suit your data (you did not give any info about this). Here is an example:
>> C{1,1} = struct('A',1:3);
>> C{2,1} = struct('A',4:6);
>> C{3,1} = struct('A',7:9);
>> cell2mat(cellfun(@(s)s.A,C,'uni',0))
ans =
   1   2   3
   4   5   6
   7   8   9
"Is there a better way?"
This task would be much simpler if you simply used one non-scalar structure, then you could simply do this:
cat(1,S.field)
[S.field]
vertcat(S.field)
etc.
For example:
>> S(1).A = 1:3;
>> S(2).A = 4:6;
>> S(3).A = 7:9;
>> vertcat(S.A)
ans =
   1   2   3
   4   5   6
   7   8   9
Do you see how much simpler the code is, because I stored the data in a much better way?
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