processLabelsMNIST.m

function Y = processLabelsMNIST(filename)
    % The processLabelsMNIST function operates similarly to the
    % processImagesMNIST function. After opening the file and reading the magic
    % number, it reads the labels and returns a categorical array containing
    % their values.
    
    dataFolder = fullfile(tempdir,'mnist');
    gunzip(filename,dataFolder)
    [~,name,~] = fileparts(filename);
    
    [fileID,errmsg] = fopen(fullfile(dataFolder,name),'r','b');
    
    if fileID < 0
        error(errmsg);
    end
    
    magicNum = fread(fileID,1,'int32',0,'b');
    if magicNum == 2049
        fprintf('\nRead MNIST label data...\n')
    end
    
    numItems = fread(fileID,1,'int32',0,'b');
    fprintf('Number of labels in the dataset: %6d ...\n',numItems);
    
    Y = fread(fileID,inf,'unsigned char');
    
    Y = categorical(Y);
    
    fclose(fileID);
    end