Regex for numeric numbers range

Question

Is there a regex that allow if number start with 1 the length will be 10 and if number start other than 1 length is 9.

Examples:

• 012345678 (since it starts with 0 the length required is 9)

• 1234567890 (since it starts with 1 the length required is 10)

I try ^[1][0-9]{8,9} but it only do for the b condition.

I need a regex that will do both conditions.

Answer 1

The ^[1][0-9]{8,9} pattern only matches strings that start with 1 and then have 8 or 9 digits, but can end with any text after these patterns.

You may use

^(?:1[0-9]{9}|[02-9][0-9]{8})$

See the regex demo

Details

• ^ - start of string
• (?: - start of a non-capturing group:
  • 1 - 1 digit
  • [0-9]{9} - any nine ASCII digits
• | - or
  • [02-9] - any ASCII digit other than 1
  • [0-9]{8} - any eight ASCII digits
• ) - end of the group
• $ - end of string.