How to read a single parameter value from multiple .mat files and store them in a new [n,1] (single column) array

Good Afternoon,

For starters, the main goal of this script would be to loop for n= number of .mat files in a directory while finding a single value under a specified variable common to all of the .mat files and aggregating these values into a new array that is [n,1].

Here is the script I'm currently stuck on:

pathname = ' ' SearchDirectory(pathname, '*Tarrays.mat'); %The .mat files holding the desired variable val

load([pathname '\FileDirectory.mat']);

for i=2:length(FileDirectory) %Ea.file,STARTING w/ 2nd one(since 1st=FDirectory itself)

load([pathname '\' strrep(FileDirectory(i,1).name, '.mat', '')]);

%Here is where I read in these variable values, BUT I'm stuck on how to create an array where the loop continuously is adding the said value so they can be saved as a single .mat array for the entire loop

SumAbs_DFM = find(Sum_STCplot_array_TfrMean_abs);

%'Sum_STCplot_array_TfrMean_abs' is the common variable amongst these .mat files

%Presumably this is where I specify the new matrix

end

save 'newmatrix' %Holding collection of the single variable values from each .mat file

An extra addition to the new matrix to preserve filenames of the .mat files where the 'Sum_STCplot_array_TfrMean_abs' values were read would also be useful, but I'm unsure where to begin as it would require another column in the new matrix

ANY help or pointers is much appreciated, as I haven't been able to find much online that I could connect with my issue!

Thank you very much!

-Reid

P.S. I still use Matlab 2012a

Answer 1

[dpb]

pathname = ' ' SearchDirectory(pathname, '*Tarrays.mat'); 
load([pathname '\FileDirectory.mat']);
for i=2:length(FileDirectory)
  load([pathname '\' strrep(FileDirectory(i,1).name, '.mat', '')]);
  SumAbs_DFM = find(Sum_STCplot_array_TfrMean_abs);
  %'Sum_STCplot_array_TfrMean_abs' is the common variable amongst these .mat files
end

Please format code in preview window before posting...

I don't know what pathname or SearchDirectory are; neither is found by a search of Matlab documentation.

I'll presume directory is in the pathname variable and the wildcard matches the .mat files wanted. If not, fix up both to match your configuration and layout.

d=dir(fullfile(pathname, '*Tarrays.mat');  % directory structure of desired files
for i=1:length(d)                % the wildcard ensures are all .mat files
  V=zeros(length(d),1);          % preallocate for the resulting array
  V(i)=load(fullfile(pathname,d(i).name, ...
            'Sum_STCplot_array_TfrMean_abs');  % store value in V
end
save('YOURNEWFILENAME.MAT',V)    % save the new array in a different file

To add the file name to the array would require either

a) making a cell array since one value would be numeric while another text, or

b) creating a second text array of same length that is the names and use the two together, or

c) using a structure array where one field is the value the other the name

Look up cell arrays and structures in the doc's for details on those options.