yield 生成器

<?php


//yield  迭代生成器
//优点  节省内存资源

/*统计内存消耗代码开始位置获取*/
$start_memory = memory_get_usage();


function create($lenth){
    for ($i=0;$i<$lenth;$i++){
        yield $i;
    }
};

foreach (create(10000) as $v){
    echo "<h5>$v</h5>";
    //var_dump($v);
}

/*......*/

/*代码末尾位置获取*/
$end_memory = memory_get_usage();
$use_memory = $end_memory - $start_memory;
$use_memory = $use_memory/1024/1024;
echo '当前脚本消耗内存大小为：'.$use_memory.'MB';