MATLAB: Import and sorting text file to matlab

data importsortstructuretext file

hi all.

I have these hundreds text files with some data i should analyze

each file has date column time column, ID column and value column.

i would like to create a structure that contains text file name and ID as fields and then fill it with the respectvie times and values. i wpould like to create a general code that can be used in every future situation, because i'm going to get more and more of this text files to analyze.

Best Answer

Import all the text files

folder = 'c:\somewhere\somefolder';
filelist = {'fileA', 'fileB', ...};  %obtained however you want. e.g with dir
alldata = cell(size(filelist));
for fileidx = 1:numel(filelist)
    %load file
    filedata = readtable(fullfile(folder, filelist{fileidx});
    %optionally, tidy up the table:
    filedata = mergevars(filedata, 1:3);
    filedata.Properties.VariableNames = {'Date', 'Time', 'ID', 'something'};
    filedata.Date = datetime(filedata.Date);
    %store in cell array
    alldata{fileidx} = filedata;
end
%once everything is loaded, merge it all in one table
alldata = vertcat(alldata{:});
%sort by time
alldata = sortrows(alldata, 'Time');

put in a structure. Not needed if all you want to plot per ID
plot each ID in one graph (I assume it's column 4 (which I called something) against time).

%create figure, axes, and tell matlab to plot all on the same graph
figure;
axes;
hold on;
%plot something vs time for each unique ID.
rowfun(@plot, alldata, 'GroupingVariables', 'ID', 'InputVariables', {'Time', 'something'});

Related Solutions

MATLAB: How to import and read multiple text files with the same name from different folders

datafolder = 'C:\somewhere\somefolder';  %your root data folder
dataname = 'RESULTS_TRIALS.txt';  %replace with appropriate extension since you haven't specified
filelist = dir(fullfile(datafolder, 'P*', 'dataname'));  %get list of dataname files in all P* subfolders of datafolder
%optional: sort filelist by the P folder number:
[~, order] = sort(str2double(regexp({filelist.folder}, '\d+$', 'match', 'once')))
filelist = filelist(order);
%loop over files and import into alldata
alldata = [];
datasize = [];
for fidx = 1:numel(filelist);
    filedata = readmatrix(fullfile(filelist(fidx).folder, filelist(fidx).name));
    if fidx == 1  %first file read. Preallocate destination matrix
        datasize = size(filedata);
        alldata = zeros([datasize, numel(filelist)]);  %preallocate 3D array 
    else   %2nd to last file, make sure the size match previous files
        assert(size(filedata) == datasize, 'Inconsistent matrix size in folder %s', filelist(fidx).folder);
    end
    alldata(:, :, fidx) = filedata;  %copy file data in destination matrix
end

MATLAB: How to write a script that outerjoins multiple data files

Something like (untested, expect typos):

folder = 'C:\dropbox';
filelist = dir(fullfile(folder, 'File*.csv'));
for fileidx = 1:numel(filelist)
    filecontent = readtable(fullfile(folder, filelist(fileidx).Name));
    if fileidx == 1
        joined = filecontent;
    else
        joined = outerjoin(joined, filecontent, 'Keys', 'Date', 'MergeKeys', true)
    end
end
writetable(joined, fullfile(folder, 'joined.csv'));

Best Answer

Related Solutions

MATLAB: How to import and read multiple text files with the same name from different folders

MATLAB: How to write a script that outerjoins multiple data files

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