Please help me with a regex to validate on a text field to accept. It should accept:

• 0
• .50
• 100
• 0.01
• 10.0
• 99.99

It shouldn't accept:

• 100.01
• 50.567

I have an almost working regex with me which accepts unlimited number of decimals, in case it helps:

^(0*100{1,1}\.?((?<=\.)0*)?%?$)|(^0*\d{0,2}\.?((?<=\.)\d*)??)$

CodePudding user response：

This regex could be the one you're looking for:

^(?:\d{1,2}\.\d{0,2}|100|\d{1,2}|\.\d{1,2})$

https://regex101.com/r/sLt1g1/1

CodePudding user response：

If you don't want to allow empty strings:

^(?:(?:\d{0,2}\.)?\d{1,2}|100|\d{1,2}\.)$

The pattern matches:

• ^ Start of string
• (?: Non capture group
  • (?:\d{0,2}\.)? Optionally match 0-2 digit and .
  • \d{1,2} Match 1-2 digits
  • | Or
  • 100 Match 100
  • | Or
  • \d{1,2}\. Match 1-2 digits and .
• ) Close non capture group
• $ End of string

Regex demo