There was a non-numeric character in $sequenceToMatch1.

"; } else { echo "

All characters were numeric in $sequenceToMatch1.

"; } $nonNumMatch = preg_match($negCharClass, $sequenceToMatch2); if ($nonNumMatch) { echo "

A non-numeric character was found in $sequenceToMatch2.

"; } else { echo "

All characters were numeric in $sequenceToMatch2.

"; } ?>