[转载]PHP 计算时间差

我们常常在网站上看到某篇文章发表于“3天前”，“5个月前”，“4年前”。下面这个函数就提供了计算这个时间差的功能。

<?php
/**
* 时间差计算
*
* @param Timestamp $time
* @return String Time Elapsed
* @author Shelley Shyan
* @copyright http://phparch.cn (Professional PHP Architecture)
*/
function time2Units ($time)
{
   $year   = floor($time / 60 / 60 / 24 / 365);
   $time  -= $year * 60 * 60 * 24 * 365;
   $month  = floor($time / 60 / 60 / 24 / 30);
   $time  -= $month * 60 * 60 * 24 * 30;
   $week   = floor($time / 60 / 60 / 24 / 7);
   $time  -= $week * 60 * 60 * 24 * 7;
   $day    = floor($time / 60 / 60 / 24);
   $time  -= $day * 60 * 60 * 24;
   $hour   = floor($time / 60 / 60);
   $time  -= $hour * 60 * 60;
   $minute = floor($time / 60);
   $time  -= $minute * 60;
   $second = $time;
   $elapse = '';

   $unitArr = array('年'  =>'year', '个月'=>'month',  '周'=>'week', '天'=>'day',
                    '小时'=>'hour', '分钟'=>'minute', '秒'=>'second'
                    );

    foreach ( $unitArr as $cn => $u )
    {
        if ( $$u > 0 )
        {
           $elapse = $$u . $cn;
            break;
        }
    }

    return $elapse;
}

$past = 2052345678; // Some timestamp in the past
$now  = time();     // Current timestamp
$diff = $now - $past;

echo '发表于' . time2Units($diff) . '前';
?>