Regular Expression - You may require the answer to match a PCRE-type regular expression. You are not required to provide answers to a question if you choose to define a regular expression as satisfying the answer. You may also offer both a regular expression and a list of answers if you wish.
(Do not start or end the expression with an escape character)
Examples:
^[A-Z]+$ - Characters from A-Z only
^[A-Z ]+$ - Characters from A-Z including space
^[A-Z0-9 ]+$- Alphanumeric characters including space
^[\x20-\x7E]+$ - ASCII characters from 32-127
See PHP.net for more information on regular expressions.
You may add a new answer by selecting the . Existing answers can be modified or deleted by using the controls to the right of the answer.