Php 使用'时存在性能影响或其他负面因素;preg#u替换';和具有多个索引的数组?
当使用“preg_replace”和带有多个索引的数组时,是否存在性能影响或其他负面因素Php 使用'时存在性能影响或其他负面因素;preg#u替换';和具有多个索引的数组?,php,arrays,performance,preg-replace,Php,Arrays,Performance,Preg Replace,当使用“preg_replace”和带有多个索引的数组时,是否存在性能影响或其他负面因素 $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'; ... $re
$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, $string);
好吧,让我看看
/** Get current time with microseconds */
function gettime() {
list($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";
事实上它甚至快了一点,但不值得注意。可能是因为它的实现中有某种优化的循环
但谁知道呢,也许有了你的数据,结果会有所不同。试着用你的数据样本做一个这样的基准测试。为了便于查找,我建议str\u replace而不是regulare expression。当您想要比较一个循环时,最好展开一个循环或使用一个Duff设备
preg_replace with arrays: 19.568552017212
preg_replace inside of a loop: 20.119801044464