泛舟湖上清波郎朗
功能function substr_startswith($haystack, $needle) {
return substr($haystack, 0, strlen($needle)) === $needle;}function preg_match_startswith($haystack, $needle) {
return preg_match('~' . preg_quote($needle, '~') . '~A', $haystack) > 0;}function substr_compare_startswith($haystack, $needle) {
return substr_compare($haystack, $needle, 0, strlen($needle)) === 0;}function strpos_startswith($haystack, $needle) {
return strpos($haystack, $needle) === 0;}function strncmp_startswith($haystack, $needle) {
return strncmp($haystack, $needle, strlen($needle)) === 0;}function strncmp_startswith2($haystack, $needle) {
return $haystack[0] === $needle[0]
? strncmp($haystack, $needle, strlen($needle)) === 0
: false;}试验echo 'generating tests';for($i = 0; $i
if($i % 2500 === 0) echo '.';
$test_cases[] = [
random_bytes(random_int(1, 7000)),
random_bytes(random_int(1, 3000)),
];}echo "done!\n";$functions = ['substr_startswith', 'preg_match_startswith', 'substr_compare_startswith', 'strpos_startswith',
'strncmp_startswith', 'strncmp_startswith2'];$results = [];foreach($functions as $func) {
$start = microtime(true);
foreach($test_cases as $tc) {
$func(...$tc);
}
$results[$func] = (microtime(true) - $start) * 1000;}asort($results);foreach($results as $func => $time) {
echo "$func: " . number_format($time, 1) . " ms\n";}结果(PHP 7.0.9)(排序最快至最慢)strncmp_startswith2: 40.2 ms
strncmp_startswith: 42.9 ms
substr_compare_startswith: 44.5 ms
substr_startswith: 48.4 ms
strpos_startswith: 138.7 ms
preg_match_startswith: 13,152.4 ms结果(PHP 5.3.29)(排序最快至最慢)strncmp_startswith2: 477.9 ms
strpos_startswith: 522.1 ms
strncmp_startswith: 617.1 ms
substr_compare_startswith: 706.7 ms
substr_startswith: 756.8 ms
preg_match_startswith: 10,200.0 msstartsWith_bench mark.php
