How to get start time and end time in php

<?php
/**
 * @author yfl  QQ554665488
 * demo Time funtion
 */
//返回今天的开始时间和结束时间
function day_now()
{
    $arr = [
        mktime(0, 0, 0, date(&#39;m&#39;), date(&#39;d&#39;), date(&#39;Y&#39;)),
        mktime(23, 59, 59, date(&#39;m&#39;), date(&#39;d&#39;), date(&#39;Y&#39;)),
    ];
    return $arr;
}

//返回昨天开始结束时间 改造上边的方法
function day_yesterday()
{
    $yesterday = date(&#39;d&#39;) - 1;
    $arr = [
        mktime(0, 0, 0, date(&#39;m&#39;), $yesterday, date(&#39;Y&#39;)),
        mktime(23, 59, 59, date(&#39;m&#39;), $yesterday, date(&#39;Y&#39;)),
    ];
    return $arr;
}

//获取当前时间的本周开始结束时间
function week_now()
{
    $arr = [
        strtotime(date(&#39;Y-m-d&#39;, strtotime("-1 week Monday", time()))),
        strtotime(date(&#39;Y-m-d&#39;, strtotime("+0 week Sunday", time()))) - 1
    ];

    return $arr;
}

// var_dump(week_now());
// echo date(&#39;Y-m-d&#39;,strtotime(&#39;next Monday&#39;,time()));
//返回上周开始和结束的时间戳
function last_week()
{
    // 1520179200   1520783999
    $arr = [
        // date(&#39;Y-m-d&#39;,strtotime(&#39;last week Monday&#39;,time())),
        // date(&#39;Y-m-d&#39;,strtotime(&#39;last week Sunday&#39;,time()))
        strtotime(&#39;last week Monday&#39;, time()),
        strtotime(&#39;last week Sunday +1 days -1 seconds&#39;, time())
    ];
    return $arr;
}

// var_dump(last_week());
// 返回本月开始和结束的时间戳
function now_month()
{
    $arr = [
        mktime(0, 0, 0, date(&#39;m&#39;), 1, date(&#39;Y&#39;)),
        mktime(23, 59, 59, date(&#39;m&#39;), date(&#39;t&#39;), date(&#39;Y&#39;))
    ];
    return $arr;
}

// var_dump(now_month());
// 返回某一年某一月的开始和结束的时间戳
function month_year($year, $month)
{
    return [
        $begin = mktime(0, 0, 0, $month, 1, $year),
        $end = mktime(23, 59, 59, $month, date(&#39;t&#39;, $begin), $year)
    ];
}

// var_dump(month_year(2017,3));

// 返回当前季度的开始时间和结束时间
function now_quarter($month = 0)
{
    $month = $month != 0 ? $month : date(&#39;n&#39;);
    $season = ceil($month / 3);
    return [
        mktime(0, 0, 0, ($season - 1) * 3 + 1, 1, date(&#39;Y&#39;)),
        mktime(0, 0, 0, $season * 3, date(&#39;t&#39;), date(&#39;Y&#39;)) - 1
    ];
}

// var_dump(now_quarter());
// 返回上个月开始和结束的时间戳
function lastMonth()
{
    $begin = mktime(0, 0, 0, date(&#39;m&#39;) - 1, 1, date(&#39;Y&#39;));
    $end = mktime(23, 59, 59, date(&#39;m&#39;) - 1, date(&#39;t&#39;, $begin), date(&#39;Y&#39;));

    return [$begin, $end];
}
// var_dump(lastMonth());