php日期计算相距多少天处理函数

在PHP程序中，很多时候都会遇到处理日期时间的问题，比如：两个时间相距天数、还有多长时间过期、到指定日期相差多少天等。

本文主要介绍3个PHP日期计算处理函数，分别是计算到指定日期还有多少天、计算两个日期相差多少天、两个日期的时间差，非常简单实用。

一、php计算到指定日期还有多少天？

function countdays($d)
{
$olddate = substr($d, 4);
$newdate = date(Y) ."".$olddate;
$nextyear = date(Y)+1 ."".$olddate;
if($newdate > date("Y-m-d"))
{
$start_ts = strtotime($newdate);
$end_ts = strtotime(date("Y-m-d"));
$diff = $end_ts - $start_ts;
$n = round($diff / 86400);
$return = substr($n, 1);
return $return;
}
else
{
$start_ts = strtotime($nextyear);
$end_ts = strtotime(date("Y-m-d"));
$diff = $end_ts - $start_ts;
$n = round($diff / 86400);
$return = substr($n, 1);
return $return;
}
}

二、php计算两个日期相差多少天

function diffBetweenTwoDays ($day1, $day2)
{
$second1 = strtotime($day1);
$second2 = strtotime($day2);
if ($second1 < $second2) {
$tmp = $second2;
$second2 = $second1;
$second1 = $tmp;
}
return ($second1 - $second2) / 86400;
}
$day1 = "2014-10-27";
$day2 = "2015-08-04";
$diff = diffBetweenTwoDays($day1, $day2);
echo $diff."\n";

三、php计算两个日期时间差

实现了类似微博中的多少天、多少月、多少年功能。

<?php
function DiffDate($date1, $date2) {
if (strtotime($date1) > strtotime($date2)) {
$ymd = $date2;
$date2 = $date1;
$date1 = $ymd;
}
list($y1, $m1, $d1) = explode('-', $date1);
list($y2, $m2, $d2) = explode('-', $date2);
$y = $m = $d = $_m = 0;
$math = ($y2 - $y1) * 12 + $m2 - $m1;
$y = round($math / 12);
$m = intval($math % 12);
$d = (mktime(0, 0, 0, $m2, $d2, $y2) - mktime(0, 0, 0, $m2, $d1, $y2)) / 86400;
if ($d < 0) {
$m -= 1;
$d += date('j', mktime(0, 0, 0, $m2, 0, $y2));
}
$m < 0 && $y -= 1;
return array($y, $m, $d);
}
?>