sorting 2d by double value.

I am getting file address on each iteration

I am trying to save in 2darray using this:

2darr(i,1) = string(file.name);

2darr(i,2) = doubleValue

Later after iteration is completed I’ll sort 2darr by doubleValue and re-iterations using loop and display into plot in doubleValue with Descending Order also the String.

How it could be done?

Answer 1

[Walter Roberson]

I suggest that you store this as two separate variables, one of which is a string array and the other of which is a numeric vector.

filenames = string({file.name});
num_files = length(filenames);
values = zeros(num_files, 1);
for K = 1 : num_files
   %do whatever
   values(K) = as_appropriate;
end

[values, idx] = sort(values, 'desc');
filenames = filenames(idx);

cats = categorical(1:num_files, 1:num_files, filenames);
plot(cats, values)

[Muhammad Awais Ali]

I tried to fit in your code in my Button callback function below is my code. i still unable to visualise how score/rank of my picutre will mapped with picure even after loop end.

on this:

app.extractFname = app.extractFname(idx);

i am getting this

Index exceeds the number of array elements. Index must not exceed 1.

[Walter Roberson]

filenames = string({file.name});

Context here is that it is expected that

file = dir(fullfile(app.diradd, '*.*'));

That is, the code

filenames = string({file.name});
num_files = length(filenames);
values = zeros(num_files, 1);

goes before the loop.

[Muhammad Awais Ali]

Actually file.name is inside loop context, we cannot put obove loop

filenames = string({file.name});

num_files = length(filenames);

values = zeros(num_files, 1);

[Walter Roberson]

You never set app.score to anything other than 0, so you are not going to get a useful plot.

function btnPushed(app, event)
           if ~strcmp(app.lbl.Text,'Database Selected Path:')
                if ~isempty(app.QueryFeatures)                    

                    app.Listbox.Items = {};                    
                    files = dir(fullfile(app.diradd,'*.*'));
                    files([files.isdir]) = [];  %remove . and .. and folders
                    filenames = fullfile({files.folder}, {files.name});
                    num_files = length(filenames);
                    
                    [~, app.extractFname, ~] = fileparts(filenames);
                    
                    arr = strings(num_files, 2);
                    
                    for idx = 1 : num_files
                        filename = filenames{idx};
                        [~, basename, ~] = fileparts(filename);
                        basename_str = string(basename);
                        iter_img = imread(filename);
                        app.iterGray = im2gray(iter_img);                   
                        app.iter_feature = extractLBPFeatures(app.iterGray, "Normalization","L2");                            
                        app.compr = pdist2(app.Q_Features, app.iter_feature, "euclidean");    
                        compr_str = string(app.compr);
                        app.Listbox.Items{end+1} = compr_str + " - " + basename_str + " -> " + idx;
                        
                        app.Panel.AutoResizeChildren = 'off';

                        ax = subplot(5, 2, idx, 'XGrid', 'on', "Parent", app.Panel);
                        imshow(ax, iter_img);
                        title(ax, basename_str + " = " + compr_str);

                        arr(i,1) = basename_str;
                        arr(i,2) = compr_str;
                        
                        app.score(idx) = 0; %?%?
                        
                        app.xset = [string(app.iter_feature) basename_str];
                        app.dataset(i,:) = app.xset;
                    end
                   
                    [app.score , idx] = sort(app.score, 'desc');

                    app.extractFname = app.extractFname(idx);

                    cats = categorical(1:num_files, 1:num_files, app.extractFname);
                    plot(cats, app.score)

                    app.DBtable.Data = app.dataset(:,:);                   
                else
                    msgbox("Selected Query Image First");
                end
            else
                msgbox("Select source Folder First");
            end
        end

Answer 2

[Muhammad Awais Ali]

Hi Thank you for your code. I am believing that the stretegy is proposed is closed to my solution.

function btnPushed(app, event)
           if ~strcmp(app.lbl.Text,'Database Selected Path:')
                if ~isempty(app.QueryFeatures)                    

                    app.Listbox.Items = {};                    
                    files = dir(strcat(app.diradd,'\*.*'));
                    
                    i = 1;
                    set = [];
                    arr=zeros((1),(2));
                    starttoend=1;
                    for file = files'
                        
                        if ~strcmp(file.name , '.') && ~strcmp(file.name , '..')   

                            iter_img=imread(fullfile(app.diradd,'\', file.name));
                            app.iterGray = im2gray(iter_img);                   
                            app.iter_feature = extractLBPFeatures(app.iterGray, "Normalization","L2");                            
                            app.compr = pdist2(app.Q_Features,app.iter_feature,"euclidean");    
                             
                            app.Listbox.Items = [app.Listbox.Items strcat(string(app.compr)," - ", file.name) , " -> " ,(string(i))];   

                            seprators = {' = '};
                            
                            app.Panel.AutoResizeChildren = 'off';

                            subplot(5,2,starttoend,'XGrid','on', "Parent",app.Panel);imshow(iter_img);title(strcat(string(file.name),seprators, string(app.compr)));
                            starttoend = starttoend + 1;

                            arr(i,1) = string(file.name);
                            arr(i,2) = string(app.compr);
                            
                            app.extractFname = string({file.name});

                            num_files = length(app.extractFname);
                            app.score = zeros(num_files, i);

                            app.xset = [app.iter_feature string(file.name)];
                            app.dataset(i,:) = app.xset;
                            i = i + 1;
                        end
                    end

                    [app.score , idx] = sort(app.score, 'desc');

                    app.extractFname = app.extractFname(idx);

                    cats = categorical(1:app.score, 1:app.score, app.extractFname);
                    plot(cats, app.score)


                    app.DBtable.Data = app.dataset(:,:);
                    
                else
                    msgbox("Selected Query Image First");
                end
            else
                msgbox("Select source Folder First");
            end
        end

[Walter Roberson]

files = dir(strcat(app.diradd,'\*.*'));

files is now a struct array that is a column vector of struct entries

for file = files'

The variable file will become each scalar struct entry in turn

arr(i,1) = string(file.name);

file is a scalar struct, and we know that the name field returned by dir() is a character vector, so file.name will be a single character vector, which you convert to string and store in arr(i,1)

app.extractFname = string({file.name});

file is a scalar struct, and we know that the name field returned by dir() is a character vector, so file.name will be a single character vector, which you wrap in a cell array and pass to string() . string() converts a cell array containing a single character vector into a scalar string() object. So just like arr(i,1) app.extractFname will be a scalar string object containing the name -- they will have the same content

num_files = length(app.extractFname);

scalar string object, so num_files will be assigned 1

app.score = zeros(num_files, i);

All of app.score will be overwritten with the 1 x 1 array of zeros.

Then after the loop you have

[app.score , idx] = sort(app.score, 'desc');

but every time through the loop, you overwrote all of app.score with a scalar 0, so after the loop, app.score is a scalar 0. You sort that 0 in descending order, gettting out a 0 for app.score and a 1 for idx