MATLAB: Load files from relative path

image analysisimage processing

    function []= read_c3d_feat(output_list_relative)
        % rather than fileread, importdata save each line separetely.
        dir_list = importdata(output_list_relative);
        dim_feat = 512;
        for i = 1 : size(dir_list, 1)
            dir_str = char(dir_list(i));
            feat_files = dir([dir_str, '/*.res5b']);
            num_feat = length(feat_files);
            feat = zeros(num_feat, dim_feat);
            for j = 1 : num_feat
                feat_path = strcat(dir_str, '/', feat_files(j).name);
                [~, feat(j,:)] = read_binary_blob(feat_path);
            end
When i give input from command line like: read_c3d_feat('C:/Users/abc/Documents/MATLAB/features/0021.res5b')
Error using dir
Invalid path. The path must not contain a null character.
Error in read_c3d_feat (line 12)
        feat_files = dir([dir_str, '/*.res5b']);
And When i give input from command line like: read_c3d_feat('C:/Users/abc/Documents/MATLAB/features')
Error using importdata (line 226)
Unable to load file.
Use TEXTSCAN or FREAD for more complex formats.
Error in read_c3d_feat (line 6)
    dir_list = importdata(output_list_relative);
Caused by:
    Error using fread
    Invalid file identifier. Use fopen to generate a valid file identifier.

Best Answer

You have not indicated what format C:/Users/abc/Documents/MATLAB/features/0021.res5b is in.
I can tell from the first situation that the first thing in the file is being interpreted as numeric 0. char() of numeric 0 is called "the null character" and it is not permitted in file names.
In the second situation, the problem is that it is not permitted to importdata() a directory name.
I suggest changing the importdata to
   dir_list = regexp( fileread( output_list_relative ), '\r?\n', 'split');
   dir_list( cellfun( @isempty, dir_list ) ) = [];       %remove empty lines
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