以我为例，wordpress网站页脚的版权声明需要更新。

想法很简单，但涉及的步骤比预期的要多。

Open footer.php in your theme's folder. Locate copyright text, expected this to be all hard coded but found: <div id="copyright"> <?php the_field('copyright_disclaimer', 'options'); ?> </div> Now we know the year is written somewhere in WordPress admin so locate that to delete the year written text. In WP-Admin, go to Options on the left main admin menu: Then on next page go to the tab Disclaimers: and near the top you will find Copyright year: DELETE the © symbol + year + the empty space following the year, then save your page with Update button at top-right of page. With text version of year now delete, we can go and add our year that updates automatically with PHP. Go back to chunk of code in STEP 2 found in footer.php and update that to this: <div id="copyright"> &copy;<?php echo date("Y"); ?> <?php the_field('copyright_disclaimer', 'options'); ?> </div> Done! Just need to test to ensure changes have taken effect as expected.

这对很多人来说可能不是同样的情况，但是我们在相当多的客户站点中遇到过这种模式，并且认为最好在这里记录。

创建一个helper函数并调用它

getCurrentYear();

function getCurrentYear(){
    return now()->year;
}

对于4位数表示:

<?php echo date('Y'); ?>

2位数表示:

<?php echo date('y'); ?>

查看php文档了解更多信息: https://secure.php.net/manual/en/function.date.php

这个给出了当地时间:

$year = date('Y'); // 2008

这个UTC:

$year = gmdate('Y'); // 2008

用M打印当前月份，用D打印日期，用Y打印年份。

<?php echo date("M D Y"); ?>

在date函数的第二个参数中可以得到更多的值 Strtotime返回参数传递的时间戳

// This work when you get time as string
echo date('Y', strtotime("now"));

// Get next years
echo date('Y', strtotime("+1 years"));

// 
echo strftime("%Y", strtotime("now"));

使用datetime类

echo (new DateTime)->format('Y');