php - 使用 'preg_replace' 和具有多个索引的数组时是否会影响性能或其他一些负面因素？

Question

使用“preg_replace”和具有多个索引的数组时是否会影响性能或其他一些负面因素？

$string = 'The quick brown fox jumped over the lazy dog.';

$patterns[0] = '/quick/';
$patterns[1] = '/brown/';
...
$patterns[100] = '/fox/';

$replacements[0] = 'bear';
$replacements[1] = 'black';
...
$replacements[100] = 'slow';

echo preg_replace($patterns, $replacements, $string);

Answer 1

走着瞧

/** Get current time with microseconds */
function gettime() {
  list($ms, $s) = explode(' ', microtime());
  return (float)$s + (float)$ms;
}

define('PAT_COUNT', 20000);

$patterns = array();
$replacements = array();
// The string will be the same for both tests
$string = '';
for ($i = 0; $i < PAT_COUNT; $i++) {
  $string .= "$i ";
  $patterns[] = "/$i /";
  $replacements[] = ":$i:";
}

$start = gettime();
$result1 = preg_replace($patterns, $replacements, $string);
echo "preg_replace with arrays: ".(gettime() - $start)."\n";

$start = gettime();
$result2 = $string;
for($i = 0; $i < PAT_COUNT; $i++) {
  $result2 = preg_replace("/$i /", ":$i:", $result2);
}
echo "preg_replace inside of a loop: ".(gettime() - $start)."\n";

输出是

preg_replace with arrays: 19.568552017212
preg_replace inside of a loop: 20.119801044464

实际上它甚至更快一点，但并不显着。也许是因为它的实现中有某种优化的循环。

但谁知道呢，也许你的数据结果会有所不同。尝试使用您的数据样本进行这样的基准测试。