Regular expression for a hexadecimal number?

Question

How do I create a regular expression that detects hexadecimal numbers in a text?

For example, ‘0x0f4’, ‘0acdadecf822eeff32aca5830e438cb54aa722e3’, and ‘8BADF00D’.

Answer 1

Just for the record I would specify the following:

/^[xX]?[0-9a-fA-F]{6}$/

Which differs in that it checks that it has to contain the six valid characters and on lowercase or uppercase x in case we have one.