<?php

function get_val1($n = 10000*100)
{
    $arr = [];
    for($i = 0; $i <= $n;$i++){
        $arr[] = $i;
        if(($i % 100000) == 0){
            echo round(memory_get_usage() / 1024 / 1024 ,2) . " MB<br>";
        }
    }
    return $arr;
}

function get_val2($n = 100)
{
    for($i = 0; $i <= $n;$i++){
        yield $i;
        if(($i % 10) == 0){
            echo round(memory_get_usage() / 1024 / 1024 ,2) . " MB<br>";
        }
    }
}
$a = get_val2();

foreach($a as $k => $v){
//    echo "$v <br>";
}

//使用生成器来读取文件
function readTxt()
{
    //1.打开文件
    $file = fopen('./a.txt','r');

    //2.读取文件
    while (!feof($file)){
        yield fgets($file , 1024);
    }

    //3.关闭文件
    fclose($file);
}

$content = readTxt();

foreach($content as $v){
    echo $v . '<br>';
}

function gen(){
    $id = 2;
    $id = yield $id;
    echo $id;
}

$gen = gen();
$gen->send(1000);