Random Number Excluding...

[Mistah_Roth]

Okay, basically I am making a script that will search a random folder, find out how many MIDIs are in that folder (the MIDIs are named 01.mid, 02.mid etc) then generate a random number to decide which midi to play.

The problem is that some MIDIs are missing, so it will be like

01.mid
02.mid
04.mid
07.mid
08.mid

etc... so in this random number I have to take into account that there are some numbers I need to exclude. This is what I currently have:

srand(time());
$rancd = (rand()%4)+1;
$num = 0;
$end = 0;

do {
	$num++;
		if ($num < 10) $num = "0".$num;
		if (file_exists("media/".$rootid."/music/midi/cd".$rancd."/".$num.".mid")) $last = $num;
		else $end++;
} while ($end < 6);
$num = $num - 1;


do {
	srand(time());
	$random = (rand()%$last)+1;

if ($random < 10) $random = "0".$random;
} while (file_exists("media/".$rootid."/music/midi/cd".$rancd."/".$random.".mid") == FALSE);

$song = ("media/".$rootid."/music/midi/cd".$rancd."/".$random.".mid");

Basically this is taking way too long to load, and its not very efficient.

so I was thinking in my loop where it checks all the MIDIs in the folder, I could make a variable $file[$num] and set each slot to a boolean value of 1 if it exists, and 0 if it doesnt.

But then in the random I'd have to somehow figure out how to make it disclude all the values assigned to 0

Any help? any better ideas?

[laserlight]

Ignore the filenames. Suppose that you have selected a directory. Just open it, loop through its contents looking for files, add the filenames to an array, then select from the array.

function randomFilename($dirpath) {
	if ($dh = opendir($dirpath)) {
		$file_array = array();
		while (($file = readdir($dh)) !== false) {
			//assume that any file in directory can be accepted
			if (is_file($file)) {
				$file_array[] = $file;
			}
		}
		closedir($dh);
		if (count($file_array) > 0) {
			return $file_array[array_rand($file_array)];
		} else {
			return false;
		}
	} else {
		return false;
	}
}

[Mistah_Roth]

Alright that seems to sort of work... but for some odd reason

if (is_file($file)) { 
                $file_array[] = $file; 
            }

The directory is being read properly, but for some reason it thinks none of the files exist, because the array value is 0. I'm not sure why this is. If I remove the "if (is_file($file))" it puts the values in properly, its just not good because you get the

.
..

as the first two values.

[laserlight]

Oh, is_file() is probably checking the file relative to the directory current script is in.
Concatenate $dirpath with $file then, to make it an absolute path.

[Drakla]

[man]glob[/man] is often a really compact way to grab an array of files.

$allMids = glob('*.mid');

or whatevery your path is

[Mistah_Roth]

Excellent, I got everything working well now, thanks a lot 🙂