MATLAB: Loading multiple matlab files in to a structure

structure: load

I'm trying to load multiple matlab files in to a structure using

 for m = 1:numel(data)
    S(m,1) = load(data{m});
end

Where data is the file path. However i have been encountering the following message.

"Subscripted assignment between dissimilar structures."

Any help appreciated

Best Answer

This means that the variables are different across files. In a structure array, all the fields should be the same, hence the error. However, the sub-fields can be different!

So, you can use this approach:

for m = 1:numel(data)
    S(m,1).content = load(data{m});
end

Related Solutions

MATLAB: How to load in .m files in a sequence to Matlab

"The problem is that I cannot load in all .m files at once..."

Your question is confusing: .m files contain code (and in general they are not loaded as data), whereas .mat files contain data variables (which can be loaded into MATLAB memory). M-files can be scripts or functons or classes, which can be run/called as appropriate. But usually it does not make much sense to load them.

I will assume that you actually have multiple .mat files, in which case you can easily prevent variables being overwritten in a loop by loading the .mat files into an output variable (which is a scalar structure)

S = load(...);

If all of the .mat files contain exactly the same variables, then that scalar structure can easily be joined into one non-scalar structure, which makes access all of the data easy:

N = number of files
A = cell(1,N);
for k = 1:N
     A{k} = load(...);
end
A = [A{:}];

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

MATLAB: How to save struct data in for loop

You can overcome the problem by pre-allocating the array of structures as follows:

clear all; % Clear the workspace
N = 10;
% Pre-allocate the array of structures
structArray1(N) = struct('field1',[], 'field2',[], 'field3',[]);
  
for i=1:N
    field1 = "field1";
    field2 = "field2";
    field3 = "field3";
    
    structArray1(i)=getStruct(field1, field2,field3);  
end

Alternatively, instead of pre-allocating before the loop, you can also loop backwards so that all the memory allocation is done in the first iteration itself.

N = 10;
for i=N:-1:1
    field1 = "field1";
    field2 = "field2";
    field3 = "field3";
    
    structArray2(i)=getStruct(field1, field2,field3);  
end
structArray2 = fliplr(structArray2);  % Get back the array of structures in correct order

The getStruct function is as follows:

function outStruct = getStruct(field1, field2,field3)
% returns a struct with 3 fields
     outStruct.field1 = field1;
     outStruct.field2 = field2; 
     outStruct.field3 = field3; 
end

Best Answer

Related Solutions

MATLAB: How to load in .m files in a sequence to Matlab

MATLAB: How to save struct data in for loop

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