PHP代码优化

PHP代码优化
1.require效果优于require_once()
require操作状态调用较少，当所需调用的PHP文件目录较深时由于require_once()每搜索一层会有一次状态调用所以大多数情况下require更为优秀
有利于提高程序效率
2.循环的优化
$array = ["1","2","3","4","5","6","7","8","9"];
for（$i=0;$i<count($array);$i++）{

}
本循环每次都需要调用count（）进行数组长度计算，而后面的8次计算属于多余。
所以
$array = ["1","2","3","4","5","6","7","8","9"];
$num = count($array);
for（$i=0;$i<$num;$i++）{

}
foreach循环遍历数组优于while和for