function call

To tell my function to perform it's operations on files in a directory Function('directory') is the command for that. how do I tell this function to perform it's operations on only the first n files in that directory and not all of the files.

Answer 1

[Grzegorz Knor]

Something like that:

function my_fun(directory,n)
a = dir(directory);
% a(1) is folder '.'
% a(2) is folder '..'
% so you have to start from a(3)
for k=3:n+2
   disp(a(k).name)
   % do more operation on folder/file
end

[Titus Edelhofer]

Hi Grzegorz,

note though, that '.' and '..' need not always be the first two entries, I don't know how I managed but I had once stumbled across a folder where the first entry was some weirdly named folder (and therefore . and .. came second and thirs).

Titus

[Grzegorz Knor]

Thank you for the advice! I thought that "." and ".." are always first.

[Daniel Shub]

I don't know the specifics of dir/ls sorting, and cannot easily find it on the web, but a file with the name !, sorts before . and .. on Linux. Now why you would want such an awful file name ...

[Fangjun Jiang]

Using a=a(~[a.isdir]) should solve the problem!

[Walter Roberson]

dir() is *not* defined to return . and .. first in any of the operating systems. dir() is defined to return the order that the operating system returns. In turn, the order returned by the operating system can depend upon the file system type -- some filesystems sort directories contents automatically and some do not (and some use tree structures.)

Answer 2

[Image Analyst]

Can't you specify a file extension to dir() and get only those specific files and not any directories?