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structure contains multiple cells with different variables in them I would like to remove variables not present in all cells

my structure (data) contains 1x3 cells horizontally. Each cell inturn contains three 1x1 structures with about 165 variables in each of them (The number of variables is not constant). I am trying to compare all variables names within these cells and then remove variables not present in all cells. This is so I can concatinate all the variables within these cells hoizontally. Below is a piece of code I have written to identify all the fieldnames from a structure called data and then concatenate them vertically. problem arises when there are missing variables, which I would then like to remove if not found on all cells within data.
flds = fieldnames(data{1,1});
for f = 1:size(flds,1)
out(f,:) = eval(['[data{1,1}.', flds{f} ,' ', 'data{1,2}.', flds{f} ,' ', 'data{1,3}.', flds{f} ,']']);


Rather than using awful anti-pattern eval, you should simply use dynamic fieldnames:
Please upload sample data by clicking the paperclip button.
Hi Stephen,
Thanks for your inputs. Will definitely look into the link you provided but I am afraid I will not be able to upload sample data since it is confidential information.
Thanks Again!

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1 Answer

Answer by Guillaume
on 12 Nov 2019
Edited by Guillaume
on 12 Nov 2019
 Accepted Answer

%identify common fields
commonfields = fieldnames(data{1});
for cidx = 2:numel(data)
commonfields = intersect(commonfields, fieldnames(data{cidx}));
%keep only the common fields in each structure
trimmeddata = cell(size(data));
for cidx = 1:numel(data)
scell = struct2cell(data{cidx}); %convert to cell for easy extraction
[tokeep, fieldindex] = ismember(fieldnames(data{cidx}), commonfields); %which rows of cell array to keep and which order to use for commonfields
trimmeddata{cidx} = cell2struct(scell(tokeep, :), commonfields(fieldindex(tokeep)), 1); %convert back into structure
merged = [trimmeddata{:}];


Thanks fior your input Guillaume, but
I get an error "Subscript indices must either be real positive integers or logicals." for line
"trimmeddata{cidx} = cell2struct(scell(tokeep, :), commonfields(fieldindex), 1); %convert back into structure"
odly enough though cidx is an integer when I checked.
Fixed, I'd forgotten to remove the indices (0) of fields to discard from fieldindex.

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