带 2 位小数的百分比的正则表达式

Question

I am looking to build 2 regex with those constraints:

• 0 to 100
• 2 decimals places (like 15.25 or 0.01)
• But 100.01 is not acceptable
• No negative number

For the second regex, I need it to go up to 200 instead of 100 but same for the rest.

Currently, I have this one for 0 to 100:

^([0-9]|[1-9][0-9]|100)?$

and this one for 200

^([01]?[0-9][0-9]?|200)?$

I can get 0 to 100 or 200 numbers but without decimal places.

Answer 1

First regex : ^([0-9]{1,2}|[0-9]{1,2}\.[0-9]{2}|100)?$

regex101.com

Second regex : ^(([01]?[0-9][0-9]?)|([01]?[0-9][0-9]?\.[0-9]{2})|200)?$

It also covers values such as 11.44 , 199.11

regex101.com

Answer 2

You can extend your regex like this:

^([0-9]|[1-9][0-9]|(?:[0-9]|[1-9][0-9])\.(?:[0-9]|[0-9][0-9])|100)?$

You can try it here: https://regex101.com/r/HBidWk/1

This is for 0-100

Answer 3

Here are the regex patterns I came up with from having understood the OP's requirements as follows...

1. As for the 1st one

   • "... from 0.00 (but not 00.00 ) to 99.99 to 100 (but not 100.00 )"

   • the pattern would be...

      /^(?:[1-9]?\d\.\d{2}|100)$/

   • ... and the explanation could be found at this pattern's test side:

     /^(?:[1-9]?\d\.\d{2}|100)$/ .

2. As for the 2nd one

   • "... from 0.00 (but not 00.00 ) to 199.99 to 200 (but not 200.00 )"

   • the pattern would be...

      /^(?:(?:1\d{2}|[1-9]?\d)\.\d{2}|200)$/

   • ... and the explanation could be found at this pattern's test side:

     /^(?:(?:1\d{2}|[1-9]?\d)\.\d{2}|200)$/ .

3. Due to a first misread from my side I also implemented a much more complex

   • "... from 100 (but not 100.00 ) to 199.99 to 200 (but not 200.00 )"

   • the pattern here is...

      /^(?:1\d{2}(?:(?<.100)\.\d{2}|\.\d[1-9])|100|200)$/

   • ... and the explanation could be found at this pattern's test side:

     /^(?:1\d{2}(?:(?<.100)\.\d{2}|\.\d[1-9])|100|200)$/ .