Predefined formats for DateTime class

Code
<?php

$tz 
= new DateTimezone('Europe/Berlin');

$dt = new DateTime();
$dt->setTimezone($tz);

echo 
'<b>available datetime formats</b>' PHP_EOL;

echo 
$dt->format(DateTime::ATOM) . PHP_EOL;
echo 
$dt->format(DateTime::COOKIE) . PHP_EOL;
echo 
$dt->format(DateTime::RSS) . PHP_EOL;
echo 
$dt->format(DateTime::W3C) . PHP_EOL;

echo 
$dt->format(DateTime::ISO8601) . PHP_EOL;
echo 
$dt->format(DateTime::RFC822) . PHP_EOL;
echo 
$dt->format(DateTime::RFC850) . PHP_EOL;
echo 
$dt->format(DateTime::RFC1036) . PHP_EOL;
echo 
$dt->format(DateTime::RFC1123) . PHP_EOL;
echo 
$dt->format(DateTime::RFC2822) . PHP_EOL;
echo 
$dt->format(DateTime::RFC3339) . PHP_EOL PHP_EOL;

echo 
'<b>create DateTime from a string with predefined format</b>' PHP_EOL;

$dt DateTime::createFromFormat(
    
DateTime::RSS,
    
'Sat, 04 Oct 2014 14:38:40 +0200'
);

var_dump($dt);

Result
available datetime formats
2017-10-17T07:35:39+02:00
Tuesday, 17-Oct-2017 07:35:39 CEST
Tue, 17 Oct 2017 07:35:39 +0200
2017-10-17T07:35:39+02:00
2017-10-17T07:35:39+0200
Tue, 17 Oct 17 07:35:39 +0200
Tuesday, 17-Oct-17 07:35:39 CEST
Tue, 17 Oct 17 07:35:39 +0200
Tue, 17 Oct 2017 07:35:39 +0200
Tue, 17 Oct 2017 07:35:39 +0200
2017-10-17T07:35:39+02:00

create DateTime from a string with predefined format
object(DateTime)#375 (3) {
["date"]=>
string(26) "2014-10-04 14:38:40.000000"
["timezone_type"]=>
int(1)
["timezone"]=>
string(6) "+02:00"
}
Used Versions
PHP 7.1, Zend 3.0, Symfony 3.2, Laravel 5.2, PHPUnit 5.6, Doctrine 2.6