how to create a regular expression to validate the numbers are not same even separated by hyphen (-) or Alpha Numeric


Requirement is : Field is made of 1 alpha character followed by 15 alpha numeric characters including maximum 2 hyphens (-)


Above Regex is working fine but as the requirement it’s not allowed the duplicate numbers like 1) N000000000000000 2)N000000-0000-0

the above 2 values not to allow as its has the same digit as "0".

>Solution :

You can use


See the regex demo. Inside the code, in your string literals, make sure you escape backslashes twice.


  • ^ – start of string
  • [A-Z] – an uppercase ASCII letter
  • (?!\D*(\d)(?:\D*\1)+\D*$) – the string cannot contain only identical digits
  • (?=.{2,15}$) – there must be 2 to 15 chars other than line break chars to the right of the current position
  • [A-Z0-9]* – zero or more ASCII uppercase letters/digits
  • (?:-[A-Z0-9]*){0,2} – zero, one or two occurrences of - and then zero or more ASCII uppercas eletters/digits
  • [A-Z0-9]+ – one or more ASCII uppercase letters/digits
  • $ – end of string.

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