regex for alphanumeric, but at least one character

Question

In my asp.net page, I have an input box that has to have the following validation on it:

Must be alphanumeric, with at least 1 character (i.e. can\'t be ALL numbers)

Answer 1

^\d*[a-zA-Z][a-zA-Z0-9]*$

Basically this means:

• Zero or more ASCII digits;
• One alphabetic ASCII character;
• Zero or more alphanumeric ASCII characters.

Try a few tests and you'll see this'll pass any alphanumeric ASCII string where at least one non-numeric ASCII character is required.

The key to this is the \d* at the front. Without it the regex gets much more awkward to do.