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run code in 200+ PHP versions simultaneously
<?php $array = array('a' => 'Hello', 'b' => 'World'); array_walk($array, 'adda'); function adda(&$value, &$key) { $key = "a".$key; } var_dump($array);

Shows result from various feature-branches currently under review from the php developers. Contact me to have additional branches featured.

Output for branch php-master
array(2) { ["a"]=> string(5) "Hello" ["b"]=> string(5) "World" }
Output for branch php-master+opcache
array(2) { ["a"]=> string(5) "Hello" ["b"]=> string(5) "World" }

Archived branches

Once feature-branches are merged or declined, they are no longer available. Their functionality (when merged) can be viewed from the main output page