Notes on Matlab

Notes on Matlab.md

Notes on Matlab

Contents

• Notes on Matlab
  • Contents
  • Get the directory name of a source file
  • Create a directory if it doesn't exist
  • Read from and write to a file
  • Print a struct to a file
  • Recursively search a directory for all files of a certain type

Get the directory name of a source file

current_filename = mfilename('fullpath');
[current_dir, ~, ~] = fileparts(current_filename);

Create a directory if it doesn't exist

dir_name = 'new_folder';

if ~exist(dir_name, 'dir')
    mkdir(dir_name)
end

Read from and write to a file

Below is a code snippet for writing strings and text to a file in Matlab.

% Get name of current file, current directory, and output filename
current_filename = mfilename('fullpath');
[current_dir, ~, ~] = fileparts(current_filename);
debug_filename = fullfile(current_dir, 'debug.txt');

% Open file and check for errors
debug_fid = fopen(debug_filename, 'w');
if debug_fid < 0
    error('Could not open file %s', debug_filename);
end

% Print to file and close
fprintf(debug_fid, 'Hello world, the answer is %i\n', 42);
fclose(debug_fid);

A convenient function for reading a text file is fileread, which accepts a string containing the filename (as opposed to a file ID, so there is no need to call fopen and check the error code), and reads the entire text file (possibly containing multiple lines) into a single string, which is returned by the function.

Print a struct to a file

A struct can be printed to a file using the evalc function, EG:

a = [1 2 3; 4 5 6];
fprintf(fopen('temp.txt', 'w'), '%s\n', evalc('disp(whos(''a''))'));

Contents of temp.txt:

          name: 'a'
          size: [2 3]
         bytes: 48
         class: 'double'
        global: 0
        sparse: 0
       complex: 0
       nesting: [1×1 struct]
    persistent: 0

Recursively search a directory for all files of a certain type

In Matlab, since R2016b (source):

filelist = dir(fullfile('dir_name', '**\*.wav'));
filelist = filelist(~[filelist.isdir]);