Table to Array conversion using a for loop

Hi! Is there a way I can do this operation within a for loop?

load 'temps-2021-11-16.mat'
temps_2021_11_16 = table2array(data(:,:));

load 'temps-2021-10-31.mat'
temps_2021_10_31 = table2array(data(:,:));

load 'temps-2021-10-15.mat'
temps_2021_10_15 = table2array(data(:,:));

load 'temps-2021-09-13.mat'
temps_2021_09_13 = table2array(data(:,:));

load 'temps-2021-09-29.mat'
temps_2021_09_29 = table2array(data(:,:));

load 'temps-2021-08-12.mat'
temps_2021_08_12 = table2array(data(:,:));

load 'temps-2021-07-27.mat'
temps_2021_07_27 = table2array(data(:,:));

load 'temps-2021-04-06.mat'
temps_2021_04_06 = table2array(data(:,:));

load 'temps-2021-03-21.mat'
temps_2021_03_21 = table2array(data(:,:));

load 'temps-2021-03-05.mat'
temps_2021_03_05 = table2array(data(:,:));

load 'temps-2021-02-17.mat'
temps_2021_02_17 = table2array(data(:,:));

Thank you so much!

[Stephen23]

temps_2021_02_17 = ..
%     ^^^^^^^^^^ do not force meta-data into variable names

unless you really want to force yourself into writing slow, complex, inefficient, obfuscated, insecure, buggy code that is hard to debug:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Those files are so neatly designed with one variable name (i.e. 'data'), it really would be such a shame to awkwardly force meta-data into variable names. Indexing is simpler and much more efficient.

Answer 1

[Jon]

I agree with @Stephen23 comments about not using dynamically named variables, here's another approach, in which you store all of the data in a single table. You can then easily retrieve data corresponding to a particular date, as shown in the end of the example code,

% get list of relevant data files
list = dir('temps-*.mat')

% loop through data files saving data into tables
tableCell = cell(numel(list),1); % cell array to temporarily hold individual tables
for k = 1:numel(list)
    load(list(k).name) % load the table

    % find number of rows in the table
    numRows = size(data,1);

    % add new first column to table with date corresponding to source file name
    [~,name] = fileparts(list(k).name)
    date = datetime(name(7:end))
    dateColumn = table(repmat(date,numRows,1),'VariableNames',{'date'});
    data = [dateColumn data]

    % put table into temporary cell array
    tableCell{k}= data;
end

% concatenate table to make overall table
dataTable = vertcat(tableCell{:})

% now if for example you want an array of data corresponding to
% 2021-10-31 you can use
idl = dataTable.date == '2021-10-31'
data = table2array(dataTable(idl,2:end))

[Jon]

Have you had a chance to try out the suggested solutions?

[Ashfaq Ahmed]

Yes! The suggestion helped! I am using this code to get the result.

list = dir('temps-*.mat');
Saved_Temp = cell(numel(list),1);
for k = 1:numel(list)
    load(list(k).name);
    Saved_Temp{k}= table2array(data(:,:));
end

[Jon]

Great, glad you got it working. Good luck with your project.

[Ashfaq Ahmed]

Thank you so much @Jon

Answer 2

[Stephen23]

A much better approach stores the imported data in the structure returned by DIR:

P = 'absolute or relative path to where the files are saved';
S = dir(fullfile(P,'*.mat'));
for k = 1:numel(S)
    F = fullfile(P,S(k).name);
    T = load(F);
    S(k).data = table2array(T.data);
end

All of the imported data will be available in the structure S, for example the 2nd file:

S(2).name
S(2).data

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