3v4l.org

run code in 300+ PHP versions simultaneously
<?php $my_key = uniqid("\x00"); if (preg_match('/[a-zA-Z]/', $my_key)) { echo "key has alpha chars\n"; } preg_replace('/[a-zA-Z]/', "4", $my_key); $var[$my_key] = TRUE; foreach($var as $key => $val) { if ($key === $my_key) { echo 'You got it right'; } else { echo 'You got it wrong'; } }
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.26, 7.3.0 - 7.3.13, 7.4.0 - 7.4.1
key has alpha chars You got it right
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180.77 ms | 405 KiB | 325 Q