3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $show = array( 'mon' => false, 'tue' => false, 'wed' => false, 'thu' => false, 'fri' => false, 'sat' => false, 'sun' => false ); $post = array(); array_walk($show, function(&$x, $i) use ($post) { $x = true; // in your case $x = isset($post[$i]); }); var_dump($show);
based on Vf6go
Output for 5.3.0 - 7.1.7, 7.2.0
array(7) { ["mon"]=> bool(true) ["tue"]=> bool(true) ["wed"]=> bool(true) ["thu"]=> bool(true) ["fri"]=> bool(true) ["sat"]=> bool(true) ["sun"]=> bool(true) }
Output for 7.1.10

Process exited with code 137.
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.2.17
Parse error: syntax error, unexpected T_FUNCTION in /in/9luc9 on line 15
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.4.1, 5.0.0 - 5.0.5
Parse error: parse error, unexpected T_FUNCTION in /in/9luc9 on line 15
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error in /in/9luc9 on line 15
Process exited with code 255.