regular expression for 5 digit number excluding '00000'

Question

i need to have a regular expression which accept atleast 1 digit number and maximum 5 digit number and if user enter zero in the following fashion like '00','000','0000','00000' then expression should reject such inputs. currently, i am using ^[0-9]{1,5}$.

Answer 1

If you'd make sure that the user's input is formatted as a 5 digit number with leading zeroes, then the following regex would work:

^[0-9]{5}(?<!00000)$

This uses negative lookbehind to ensure that the string entered was not 5 zeroes.