PHP date and time application eight: add or subtract the number of days from a specific date

In this article "PHP date and time application seven: Get the date and day of the week in a certain country", I introduced to you how to get the date and day of the week in a certain country; continue the date and time today Using the series of exercises~

The topic of this article is "How to write a PHP script to add/subtract the number of days from a specific date".

To put it simply, let us use PHP to output the date how many days ago and how many days after.

If you still don’t understand, let’s look at the code directly:

The PHP code is as follows:

<?php

$dt=&#39;2021-09-15&#39;;
echo &#39;原始日期 : &#39;.$dt."<br>";
$no_days = 50;
$bdate = strtotime("-".$no_days." days", strtotime($dt));
$adate = strtotime("+".$no_days." days", strtotime($dt));
echo &#39;50天前 : &#39;.date("Y-m-d", $bdate)."<br>";
echo &#39;50天后 : &#39;.date("Y-m-d", $adate)."<br>";

The output result is:

Now you understand!

In the above code, we gave a specified date "2021-09-15", and then specified a number of days "50".

Finally, use the -, operator to find the date 50 days before and 50 days after the date.

Of course there are two important functions that everyone needs to master, namely strtotime and date:

strtotime()The function of the function is to Any English text date or time description is resolved to a Unix timestamp (number of seconds since January 1 1970 00:00:00 GMT).

Note:

For dates in m/d/y or d-m-y format, if the separator is a slash (/), the American m/d/y format is used. If the delimiter is a dash (-) or a dot (.), the European d-m-y format is used. To avoid potential errors, you should use YYYY-MM-DD format whenever possible or use the date_create_from_format() function.

date()The function is to format the local date and time and return the formatted date string.

Note:

PHP 5.1.0: Added E_STRICT and E_NOTICE time zone errors. The valid range of timestamps is from Friday, December 13, 1901 20:45:54 GMT to January 2038. Tuesday, 19 May 03:14:07 GMT In versions prior to 5.1.0, on some systems (such as Windows) timestamps were limited to from 01-01-1970 to 19-01-2038.

PHP 5.1.1: Added standard date/time format constants for specifying format parameters.

Finally, I would like to recommend the latest and most comprehensive "PHP Video Tutorial"~ Come and learn!

The above is the detailed content of PHP date and time application eight: add or subtract the number of days from a specific date. For more information, please follow other related articles on the PHP Chinese website!