[ACCEPTED]-How do you get the size of a file in MATLAB?-file-io

Accepted answer
Score: 56

Please see the dir function as stated above.

Please 2 note that the dir function works on files 1 and not on directories only.

>> s = dir('c:\try.c')

s = 

       name: 'try.c'
       date: '01-Feb-2008 10:45:43'
      bytes: 20
      isdir: 0
    datenum: 7.3344e+005
Score: 23

You can use the DIR function to get directory 5 information, which includes the sizes of 4 the files in that directory. For example:

dirInfo = dir(dirName);  %# Where dirName is the directory name where the
                         %#   file is located
index = strcmp({dirInfo.name},fileName);  %# Where fileName is the name of
                                          %#   the file.
fileSize = dirInfo(index).bytes;  %# The size of the file, in bytes

Or, since 3 you are looking for only one file, you can 2 do what Elazar said and just pass an absolute 1 or relative path to your file to DIR:

fileInfo = dir('I:\kpe\matlab\temp.m');
fileSize = fileInfo.bytes;
Score: 7

Use the fact that MatLab has access to Java 1 Objects:

myFile = java.io.File('filename_here')
flen = length(myFile)
Score: 5

If you don't want to hardcode in your directory, you 3 can use the built in pwd tool to find the 2 current directory and then add your file 1 name to it. See example below:

FileInfo = dir([pwd,'\tempfile.dat'])
FileSize = FileInfo.bytes
Score: 2

The question seems to indicate that fopen/fread/.. is 4 used. In this case, why not seeking to the 3 end of the file and reading the position?


function file_length = get_file_length(fid)
% extracts file length in bytes from a file opened by fopen
% fid is file handle returned from fopen

% store current seek
current_seek = ftell(fid);
% move to end
fseek(fid, 0, 1);
% read end position
file_length = ftell(fid);
% move to previous position
fseek(fid, current_seek, -1);


Matlab 2 could have provided a shortcut..

More on 1 ftell can be found here.

Score: 1

This code works for any file and directory 1 (no need for absolute path) :

    index = strcmp({dirInfo.name},[filename, '.ext']); % change the ext to proper extension 
    fileSize = dirInfo(index).bytes

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