Finding common prefix on array of strings

[beakerboy]

I have an array of strings. Each string may begin with a common substring of unknown length. I'm looking for a more elegant solution than what I have. Is there a way to quickly "boolean and" all the strings and take everything before the first 8 bytes of zeros. Any ideas for something more econimical or fewer lines of code than what I have? I'm just thinking there has to be an easier way to do this.
Thanks,
Kevin

$prefix="";
$test_length = 1
$test_prefix = substr($list[$i],0,$test_length);

while ($pass) {
     for ($i=0;$i<count($list);$i++) {
          if ( substr($list[$i],0,$test_length) != $test_prefix) $pass = false;
     }
     if ($pass) {
          $prefix = $test_prefix;
          $test_length++;
          $test_prefix = substr($list[0],0,$test_length);
     }
}

[frost110]

What is housed in $list

--FrosT

[Weedpacket]

Could you give us some example data so that we can get a better idea of what the code is supposed to do, and what the results are supposed to be (is it just a pass/fail, the value of $prefix, or what?) - and what these "8 bytes of zeros" are of which you speak? In short - an elegant solution to what?

However, straight off I can see that a simple break statement could simplify the loop a wee bit:

while (true) {
	for ($i=0;$i<count($list);$i++) {
		if ( substr($list[$i],0,$test_length) != $test_prefix)
			break;
	}
	$prefix = $test_prefix;
	$test_length++;
	$test_prefix = substr($list[0],0,$test_length);
}

The [man]array_filter[/man] function (perhaps along with some of the other functions in the same section) may help.