PHP中FOR与FOREACH的性能
与“ for”循环相比,“ foreach”比较慢。foreach复制需要在其上执行迭代的数组。
为了提高性能,需要使用引用的概念。除此之外,“ foreach”易于使用。
示例
以下是一个简单的代码示例-
<?php$my_arr = array();
for ($i = 0; $i < 10000; $i++) {
$my_arr[] = $i;
}
$start = microtime(true);
foreach ($my_arr as $k => $v) {
$my_arr[$k] = $v + 1;
}
echo "This completed in ", microtime(true) - $start, " seconds";
echo "<br>";
$start = microtime(true);
foreach ($my_arr as $k => &$v) {
$v = $v + 1;
}
echo "This completed in ", microtime(true) - $start, " seconds";
echo "<br>";
$start = microtime(true);
foreach ($my_arr as $k => $v) {}
echo "This completed in ", microtime(true) - $start, " seconds";
echo "<br>";
$start = microtime(true);
foreach ($my_arr as $k => &$v) {}
echo "This completed in ", microtime(true) - $start, " seconds";
?>
输出结果
这将产生以下输出-
This completed in 0.00058293342590332 secondsThis completed in 0.00063300132751465 seconds
This completed in 0.00023412704467773 seconds
This completed in 0.00026583671569824 seconds
以上是 PHP中FOR与FOREACH的性能 的全部内容, 来源链接: utcz.com/z/334950.html