gistfile1.php

<?php

function test($str){
	list($var) = explode('/', $str);
	return $var;
}

function test2($str){
	$var = array_shift(explode('/', $str));
	return $var;
}

function test3($str){
	preg_match('/^([^\/]*)/', $str, $match);
	return $match[1];
}

$str = 'some/test/string';

$time_start = microtime(true);
for($i = 0; $i <= 1000000; $i++){
	test($str);
}
$time_end = microtime(true);
$time = $time_end - $time_start;
echo "list() + explode(): {$time} seconds\r\n";

$time_start = microtime(true);
for($i = 0; $i <= 1000000; $i++){
	test2($str);
}
$time_end = microtime(true);
$time = $time_end - $time_start;
echo "array_shift() + explode(): {$time} seconds\r\n";

$time_start = microtime(true);
for($i = 0; $i <= 1000000; $i++){
	test3($str);
}
$time_end = microtime(true);
$time = $time_end - $time_start;
echo "preg_match(): {$time} seconds\r\n";

/**
 * list() + explode(): 1.0205271244049 seconds
 * array_shift() + explode(): 2.2764458656311 seconds
 * preg_match(): 1.7891898155212 seconds
 */