I want to read an excel file by entering the column and first line and last line.

Is there an ability in matlab by which I could read any file that I want. for example I have written a code as follows

q_c = readmatrix('CPTU1.xlsx','Sheet','results','Range','B3:B2993');

f_s = readmatrix('CPTU1.xlsx','Sheet','results','Range','C3:C2993');

U_2 = readmatrix('CPTU1.xlsx','Sheet','results','Range','D3:D2993');

nrows = 2991;

in this code I have to write name of the file sheet range and then calculate number of rows manually for each of my files. there are softwares in which for exaple ask the file and then column and first line and last line. can I write a code in this form. because I have a lot of file that I have to analyze them (their row number are different). If for each of them I want to modify I will have a lot of m-file and also it wastes my time.

[dpb]

You can write code to do whatever you want, of course...see uigetdir uigetfile for the file open dialogs; it's easy to use uidropdown with the sheet names to let user select a given sheet. There's rarely any point in specifying explicit ranges; the routines will read the data in the worksheet used area automagically and it's almost always simpler to just select any subsets from the whole thing in code if there are subsets of interest instead.

Don't hardcode stuff like any of this and don't name multiple variables of related function; use arrays or tables or structures instead for programmatically specifying specific variables.

[Mohammad Sadegh Nasirianfar]

I do not want to slect only the file and display it in Matlab as a folder named CPTU.xlsx. I want to get the given columns for analyzing and doing some operation on them afterwards.

[dpb]

Yes, you ask for the file name or the directory and then process everything in the folder or whatever other sequence you want -- MATLAB is a general programming system; it's up to you to decide how you want to use it and develop a script/application for your purposes. The MathWorks (TMW) can't predict what any given user wants to do and MATLAB is NOT another application with a more constricted set of facilities.

Just as you can select files with user-friendly tools that are bundled into MATLAB, nothing prevents you from asking the user for the column information, too...but it's generally not needed when reading the file; you can write code to process the desired columns based on content of the data or the found variable names.

A user-friendlier way to go at it could be to first select and read the file, then present the variable names found by column in a dropdown listbox for the user to select. This would be handy if the file format changes -- if the files are all of a given structure, you could preset those names.

"The choice is yours..."

[dpb]

OK, it so happens I have an app that lets user select files and sheets to use from a menu; it's not much code at all to do -- here are the two menu callback routines for one file and then the sheet...

    % Menu selected function: BillingFileMenu
    function BillFileFunction(app, event)
      filestr=fullfile(app.billPath,'*Bill*.xlsx');
      [app.billFile,app.billPath]=uigetfile(filestr,'Select Desired Billing File',"MultiSelect","off");
      app.billQualFile=fullfile(app.billPath,app.billFile);
      if isempty(app.billSheet),app.billSheet='Must Set Billing Sheet';end
      try
        app.BillingFolderTextArea.Value=app.billPath;
        app.BillingFfileTextArea.Value=app.billFile;
        app.BillingSheetTextArea.Value=app.billSheet;        
      catch 
        % leave unchanged; if nothing there, catch it when trying to run update
      end
    end

    % Menu selected function: BillingSheetMenu
    function BillingSheetMenuSelected(app, event)
      if ~exist(app.billQualFile,'file')
        errordlg([app.billQualFile "Not Found.  Must Set Billing File First."])
        return
      end
      sheets=sheetnames(app.billQualFile);
      if isempty(app.billSheet), app.billSheet=sheets(1); end
      iv=find(contains(sheets,app.billSheet,'IgnoreCase',false));
      if isempty(iv)||numel(iv)>1, iv=1; end
      ix=listdlg('PromptString','Select Billing Sheet','ListString',sheets,'selectionmode','single','initialvalue',iv);
      if isempty(ix), ix=iv; end
      app.billSheet=sheets(ix);
      app.BillingSheetTextArea.Value=app.billSheet;       
    end

A MATLAB application uses a global structure named app the fields in it are either user-definable or the provided GUI component handles; all the file and sheet functions need to do is to store the user-selected values into the appropriate global variable; when the "Start" button is pressed, it uses the file name and sheet as the arguments to pass to readtable -- well, that routine isn't much to look at, either...

    % Button pushed function: UpdateButton
    function UpdateButtonPushed(app, event)
      app.UpdateButton.Enable='off'; app.UpdateButton.Text="Working"; app.UpdateButton.FontColor='r';
      app.QuitButton.Enable='off';
      drawnow nocallbacks
      if ~isfile(app.billQualFile)
        h=errordlg([app.billQualFile "Not Found.  Must Set Billing File First."],'modal');
        waitfor(h)
        app.UpdateButton.Text="Update"; app.UpdateButton.FontColor='k'; app.UpdateButton.Enable='on';
        app.QuitButton.Enable='on';
        drawnow
        return
      end
      sheets=sheetnames(app.billQualFile);
      if ~contains(sheets,app.billSheet,'IgnoreCase',false)
        h=errordlg([app.billSheet "Not Found.  Must Set Billing Sheet First."]);
        waitfor(h)
        app.UpdateButton.Text="Update"; app.UpdateButton.FontColor='k'; app.UpdateButton.Enable='on';
        app.QuitButton.Enable='on';
        drawnow
        return
      end
      % Make sure user doesn't have file locked/open in another process first...
      % Excel creates hidden file with "~$" prefix while open; search for this file
      chkOpen=true;
      while chkOpen
        [~,fn]=system(['dir /a:h /b "' fullfile(app.awardPath,['~$' app.awardFile]) '"']);
        chkOpen=matches(strtrim(fn(3:end)),app.awardFile,'IgnoreCase',true);
        if chkOpen
          h=errordlg([app.awardFile "Locked for Edit.  Must Close Award File First."], ...
                      'File Locked',"non-modal");
          waitfor(h)
        end
      end
      % If UpdateSplits requested make sure user doesn't have bill file open, too
      % Excel creates hidden file with "~$" prefix while open; search for this file
      if app.billUpdate
      chkOpen=true;
        while chkOpen
          [~,fn]=system(['dir /a:h /b "' fullfile(app.billPath,['~$' app.billFile]) '"']);
          chkOpen=matches(strtrim(fn(3:end)),app.billFile,'IgnoreCase',true);
          if chkOpen
            h=errordlg([app.billFile "Locked for Update.  Must Close Billing File First."], ...
                      'File Locked',"non-modal");
            waitfor(h)
          end
        end
      end
      if ~isfile(app.billQualFile)
        h=errordlg([app.billQualFile "Not Found.  Must Set Billing File First."],'modal');
        waitfor(h)
        app.UpdateButton.Text="Update"; app.UpdateButton.FontColor='k'; app.UpdateButton.Enable='on';
        app.QuitButton.Enable='on';
        drawnow
        return
      end
      % insert a progress dialog for grins...
      h=uiprogressdlg(app.RestrictedFundsAwardsWorkbookUpdateToolUIFigure, ...
        "Title",'Please Standby...',"Message",'Reading Billing',"Indeterminate","on");
      % and finally, do the work...
      [tBill,tPay]=readBilling(app.billQualFile,app.billSheet,app.billUpdate);
      h.Message='Writing Awards';
      writeAwards(tBill,tPay,app.year,app.semester,app.awardQualFile,app.awardSheet);
      h.Message='Update Complete';
      pause(0.5)
      close(h)
      app.UpdateButton.Text="Update"; app.UpdateButton.FontColor='k'; app.UpdateButton.Enable='on';
      app.QuitButton.Enable='on';
      drawnow
      % see if user asked to open file...
      if app.OpenFileOnCompletionCheckBox.Value
        winopen(app.awardQualFile)
      end      
    end

Almost all of the above is just error checking and doing the housekeeping for the GUI; if one just looks at the sequence, it all boils down to just one line

% Button pushed function: UpdateButton
function UpdateButtonPushed(app, event)
  % error handling code elided for brevity...
  %...
  % to here
  % and finally, do the work...
  [tBill,tPay]=readBilling(app.billQualFile,app.billSheet,app.billUpdate);
  % resetting to activate buttons when done processing code elided for brevity...
  %...
  % to here
end

that passes the file name and sheet to the working function that in turn calls readtable with those to open the specific file and sheet.

As suggested, it doesn't bother to try to fix the range to read a priori; it reads the file and infers from it the size and knows what to do with the data in the file.

[Mohammad Sadegh Nasirianfar]

thank you very much.