How can I save structures from a cellarray into individual .mat files with a loop?

I want to be able to change a whole folder of a dataset all at once in the same way, just with an extension of the given names of the files and save it in a new folder. To read and process the data I don't have any Problem. But when I'm using the code as below (4.), each generated file contains all the informations. e.g. A contains only the infromations of A, but A_cut contains the processed information of the prepared A and B.

Below you find my code:

1. Is for generating what my data looks like.
2. Is How I read all of the folders in one cell array without loosing any information
3. is to prepare them
4. is where I don't know what the Problem is.

clear all

% 1.Create data (according to the data i'm actually using)
A.spc=rand(100,1);
A.wavenumber=[1:100].';
A.header={'first','second','third'}.';

B.spc=rand(100,1);
B.wavenumber=[1:100].';
B.header={'first','second','third'}.';

%save the data as file
save('A.mat','A')
save('B.mat','B')

%% 2.read data
clear all
clc
location=uigetdir;
info=dir([location,'\*.mat']);
filenames={info(:).name};
data=cell(length(info),1);

for i=1:length(info)
    fullname=[location,'\',info(i).name];
    data{i}=importdata(fullname,'\t',14,0);
end

%% 3.data procession
datacut=data; %for header information

for j = 1:length(data)
datacut{j,1}.wavenumber = data{j,1}.wavenumber(j, :);
datacut{j,1}.spc = data{j,1}.spc(j, :);
end

%% 4.save data

savepath=uigetdir(cd,'Save to folder');
str_affix = inputdlg('Enter string affix:','String Affix',[1 50],{'cut'});

for i = 1:length(data)
    c_string=string(strcat(savepath,'\',erase(info(i).name,'.mat'),'_',str_affix,'.mat'));
    save(c_string, 'datacut');
end

[Stephen23]

Rather then concatenating strings:

c_string=string(strcat(savepath,'\',erase(info(i).name,'.mat'),'_',str_affix,'.mat'));

it is recommended to use fullfile:

[~,name] = fileparts(info(i).name);
name = sprintf('%s_%s.mat',name,sffx);
name = fullfile(savepath,name);

[Stebe Hauser]

thanks for your Input!

I'm not that fluent in Matlab, so I'm actually not sure if I put it on the right place like this:

for i = 1:length(data)
    [~,name] = fileparts(info(i).name);
    name = sprintf('%s_%s.mat',name,str_affix);
    name = fullfile(savepath,name);
    tmp=datacut{:};
    save(name, 'tmp'); 
end

But when I do, it gives me this Error codes:

Error using sprintf

Function is not defined for 'cell' inputs.

Error in cut (line 66)

name = sprintf('%s_%s.mat',name,str_affix);

[Stephen23]

The output of inputdlg is a cell array, so you will need to use cell indexing to get the content of the first cell:

name = sprintf('%s_%s.mat',name,str_affix{1});
%                                        ^^^ content of first cell

https://www.mathworks.com/help/matlab/matlab_prog/access-data-in-a-cell-array.html

Answer 1

[Bob Thompson]

It is saving all of the data because you are not indexing your save selection.

save(c_string,'datacut');

You will need to create a temporary variable which contains just the desired cell, as you cannot index in the save command directly.

tmp = datacut{:};
save(c_string,'tmp')

[Stebe Hauser]

Thanks for your help!

Although I have only one set of data in each file left, all of the files contains the same data, of the first dataset, when I'm using it like this:

savepath=uigetdir(cd,'Save to folder');
str_affix = inputdlg('Enter string affix:','String Affix',[1 50],{'cut'});

for i = 1:length(data)
    c_string=string(strcat(savepath,'\',erase(info(i).name,'.mat'),'_',str_affix,'.mat'));
    tmp = datacut{:};
    save(c_string,'tmp');
end

when you compare:

datacut{1, 1}.spc
datacut{2, 1}.spc

you see, they are different, but when you compare A_cut.mat with B_cut.mat there are the same values.

[Stephen23]

"... but when you compare A_cut.mat with B_cut.mat there are the same values."

Sure, because within the loop the data that you refer to is exactly the same on each loop iteration. In fact you told MATLAB to take the content of the first cell of datacut:

tmp = datacut{:};
%            ^^^ comma separated list.
%^^              first cell's content.

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists

You will need to use indexing to access a different cell's data on each loop iteration, e.g.:

tmp = datacut{i};
%             ^ loop index

[Stebe Hauser]

Ok. Looks like everything works now, thanks!