Error using == Matrix dimensions must agree

Here is my code:

I am facing following the error:

File2 =

'BD'

ncell =

[]

Error using ==

Matrix dimensions must agree.

Error in PBM_BR_COAL_app_4_temp/IN_Button (line 395-mentioned in the code as comment %error line%)

B=A(find(row==ncell),:)

I have attached the excel here for clarity of the work. The code will fatch the data from the excel. I am not getting direction out of this error.

function IN_Button(app, event)
            
            [file,path] = uigetfile('*.xls','Select the excel file');
            
            f = fullfile(path,file) ;
            app.file.Value=file;app.path.Value=path;
            
            
            sheet = 'Overall Statistics';
            DS = xlsread(f,sheet,'J:J');
            % DS=OS(:,9);
            DS(find(isnan(DS)))=[];
            NF=xlsread(f,sheet,'R:R');%OS(:,17);
            NF(find(isnan(NF)))=[];
            NF(end)=[];
            
            ind=find(DS>7);
            NF(ind)=[];DS(ind)=[];
            
            app.dia=DS;
            app.num_freq=NF;
            app.dia_in=DS;
            app.num_freq_in=NF;
            
            cla(app.NF_fig_ExpData)
            
            %             plot(app.NF_fig_ExpData,DS,NF,'-s','DisplayName',string([file,'-Sanja-Stat']))
            
            app.FileEditField.Value=app.file.Value;
            %             ***************************************
            f = 'D:\HMMC\BD.xlsx';
            
            %             [file,path] = uigetfile('*.xlsx','Select the excel file');
            
            %             f = fullfile(path,file) ;
            A = xlsread(f);
            file2=app.file.Value;
            ind=find(file2=='.');
            file2(ind:end)=[]
            ncell=str2num(file2(4:end))
            
            row=A(:,1);
            B=A(find(row==ncell),:)   % error line%
            app.TKE.Value=B(2);
            app.VF_DF.Value=B(3)/100;
            rs=B(4);bs=B(5);
            HIST_Button(app, event)
            
        end

[KSSV]

What exactly you are trying to do from the excel file data?

[Manthan]

I am working on the GUI that takes data (excel file) and return to back end code.

GUI image is attached

Answer 1

[Mohammad Sami]

I assume you are trying to extract a number from the file name.

Your code assumes that the file name is 4 characters or longer.

It also assumes that numeric value in the filename is starts from character 4 until the end of the filename.

However the file name you use is only 2 chars 'BD' and has no numeric values in it.

A better option would be to use pattern matching rather then using fixed offsets.

You will also need to check that the output is not empty and if there are more then one sequence you will need to see which one you want to use or write a specfic pattern for matching exactly what you require.

More information on pattern is available here R2020b ++

https://www.mathworks.com/help/matlab/ref/pattern.html

For older version of matlab you can use regexp function with regex expression to match what you need.

https://www.mathworks.com/help/matlab/ref/regexp.html?s_tid=doc_ta

a = 'somefile124.xlsx';
p = digitsPattern; % matches one or more digits.
out = extract(a,p)

out = 1×1 cell array
    {'124'}

a = 'somefile_123.456.xlsx'; % multiple digit sequence in the filename
out = extract(a,p)

out = 2×1 cell array
    {'123'}
    {'456'}

length(out)

ans = 2

a = 'somefile_nonumber.xlsx';
out = extract(a,p)

out =

  0×1 empty cell array

length(out)

ans = 0

[Manthan]

Thank you for the response. What I am trying to do is the GUI will take data inside the excel file and return it to backend code.