day and date in php code example

Example 1: php get day from date

$timestamp = strtotime('2009-10-22');

$day = date('D', $timestamp);
var_dump($day);

Example 2: date in php

FYI: there's a list of constants with predefined formats on the DateTime object, for example instead of outputting ISO 8601 dates with:

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

or

<?php
echo date('Y-m-d\TH:i:sO');
?>

You can use

<?php
echo date(DateTime::ISO8601);
?>

instead, which is much easier to read.