How to read all text files in a folder with unknown number of files?

I have an unknown number of text files that need to be read and put into tables, and then all of those tables need to be combined to 1 table and plotted in a GUI created in Matlab's GUIDE. I have attached two such text files.

I previously found out that in order to collect the data from each of these files, I would have to run the following code.

Day1 = 'SI010218.log';
opts = detectImportOptions(Day1);
opts = setvartype(opts,1,'datetime');
opts = setvaropts(opts,1,'InputFormat','dd.MM.uuuu HH:mm:ss');
table1 = readtable(Day1,opts);

Which would save that text file's data into a table named table1. I think I should add this to the

_OpeningFcn(
in the GUIDE.

Thing is, how do I let the code scan through an entire folder and read all the tables in it, and combine it all into one table?

Answer 1

[Benjamin Kraus]

You can use the dir command to generate a list of files that match a specific pattern. Once you've done that, can you loop over the list of files and run the code block you pasted, except with the Day1 variable replaced by the file name. Then you need to concatenate the tables.

It might look something like this:

f = dir('*.log');
alldatatable = [];
for ii = 1:numel(f)
    DayFile = f(ii).name;
    opts = detectImportOptions(DayFile);
    opts = setvartype(opts,1,'datetime');
    opts = setvaropts(opts,1,'InputFormat','dd.MM.uuuu HH:mm:ss');
    table1 = readtable(DayFile,opts);
    if isempty(alldatatable)
        alldatatable = table1;
    else
        alldatatable = [alldatatable; table1];
    end
end

You may need to modify how the tables are joined, and you can probably consolidate some of the other code (such as detectImportOptions) if the files are all the same format, but this is the general approach to consider.

[Chamath Vithanawasam]

This does work, after I replace 'DayData' at line 8 with 'DayFile'. Was that a mistake? Because 'DayData' was not declared.

[Benjamin Kraus]

Yes, that was a mistake. I've updated the code. Glad you got it working.