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

The theme of this article is “ How to write a PHP Script to add / Subtract the number of days from a specific date ”.

Let's use PHP How many days before output , How many days later .

1. Look directly at the code

PHP The code is as follows ：

1 2 3 4 5 6 7 8 9

<?php $dt='2021-09-15'; echo' Original date : '.$dt."<br>"; $no_days= 50; $bdate= strtotime("-".$no_days." days", strtotime($dt)); $adate= strtotime("+".$no_days." days", strtotime($dt)); echo'50 Days ago, : '.date("Y-m-d", $bdate)."<br>"; echo'50 Days later : '.date("Y-m-d", $adate)."<br>";

In the above code , We gave a date “2021-09-15”, Then a number of days was specified “50”.

Finally through -、+ The operator finds the date 50 Days ago and 50 Days after .

Of course, there are two important functions that you need to master , Namely strtotime and date：

strtotime() The function parses the date or time description of any English text into Unix Time stamp （ since January 1 1970 00:00:00 GMT Seconds from ）.

notes ：

m/d/y or d-m-y Format date , If the separator is a slash （/）, The American m/d/y Format . If the separator is a horizontal bar （-） Or point （.）, Use European d-m-y Format . To avoid potential mistakes , You should use... Whenever possible YYYY-MM-DD Format or use date_create_from_format() function .

date() The function formats the local date and time , And returns the formatted date string .

notes ：

PHP 5.1.0： newly added E_STRICT and E_NOTICE The timestamp of the valid range of time zone error is from 1901 year 12 month 13 Japan 20:45:54 GMT Friday To 2038 year 1 month 19 Japan 03:14:07 GMT Tuesday 5.1.0 Previous version , On some systems （ for example Windows） The timestamp is limited from 01-01-1970 To 19-01-2038.

PHP 5.1.1： New standard date / Time format constants , Is used to specify the format Parameters .