PHP 如何找到下一个 1 月 1 日之前的天数（不指定年份）？

Question

How do I find out the number of days until the next January 1 without specifying a year?

I always want to know how many days until the next January 1, so I don't want to say "how many until Jan 1, 2020" or I'll need to reset my variable every year.

Answer 1

You can use DateTime objects to do the math. Create one object which is today, and another which is January 1 , to which we then add a year, and then take the difference:

$today = new DateTime();
$jan1 = new DateTime('January 1');
$jan1->modify('+1 year');
$days = $today->diff($jan1)->days;
echo "$days days until January 1\n";

Output (on December 6)

25 days until January 1

Demo on 3v4l.org