How to detect exact length in regex

Question

I have two regular expressions that validate the values entered.

One that allows any length of Alpha-Numeric value:

@\"^\\s*(?[A-Z0-9]+)         


        

Answer 1

This should match only 10 digits and allow arbitrary numbers of whitespaces before and after the digits.

Non-capturing version: (only matches, the matched digits are not stored)

^\s*(?:\d{10})\s*$

Capturing version: (the matched digits are available in subgroup 1, as $1 or \1)

^\s*(\d{10})\s*$