php array

<pre name="code" class="php"><?php/** * for  foreach array_reduce 执行效率比较： * 综合下来 foreach 最快 for 次之  array_reduce 最慢（相差一个小数点，但是代码写起来很有水平，一行代码搞定） */$a=[1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,10,1,2,3,4,5,6,7,8,9,10,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,10,1,2,3,4,5,6,7,8,9,10,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,10,1,2,3,4,5,6,7,8,9,10,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,10,1,2,3,4,5,6,7,8,9,10,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,1,2,3,4,5,6,7,8,9,10,];/** * Simple function to replicate PHP 5 behaviour */function microtime_float(){    list($usec, $sec) = explode(" ", microtime());    return ((float)$usec + (float)$sec);}$time_start = microtime_float();//显得很有水平，其实数度最慢array_reduce($a,function($v1,$v2){$v1 += $v2;return $v1;});$time_end = microtime_float();$time = $time_end - $time_start;echo "array_reduce spent $time seconds\n";echo "<hr>";$time_start = microtime_float();$count = 0;foreach($a as $val){$count += $val;}$time_end = microtime_float();$time = $time_end - $time_start;echo "foreach spent $time seconds\n";echo "<hr>";$time_start = microtime_float();$count = 0;$num = count($a);for($i=0;$i<$num;$i++){$count += $val;}$time_end = microtime_float();$time = $time_end - $time_start;echo "for $time seconds\n";