Regular expression which validates whether the number is in between 0.00 to 20.00

Question

I have searched a lot also tried but it is not working for me. I am using java script.

update your question with code. what regular expression you are trying? — kudlatiger, Apr 13 '16 at 10:03
Are the boundaries `0.00` and `20.00` *included* or *excluded*? Is `1.9999999999` a valid input or you require *exactly two* digits after decimal point? Could, please, you provide *some examples*? — Dmitry Bychenko, Apr 13 '16 at 10:05
using regular expressions for validating numeric ranges is not recommended. http://stackoverflow.com/questions/22130429/using-regular-expressions-to-validate-a-numeric-range — kudlatiger, Apr 13 '16 at 10:05
@Bikram Sahu: and what about *leading zero*? E.g. `05.00` is it a valid input? — Dmitry Bychenko, Apr 13 '16 at 10:16

Dmitry Bychenko · Answer 1 · 2016-04-13T10:47:53.217

1

Providing that

Both borders are included (so 0.00 and 20.00 are valid)
Two digits after the decimal point are mandatory (5 in invalid, but 5.00 is OK)
Leading zeros are invalid (so 05.00 is invalid)

the regular expression can be

(^1?[0-9]\.[0-9]{2}$)|(^20\.00$)

Edit: if requests are

Both borders are included (so 0.00 and 20.00 are valid)
There're at most two digits after the decimal point(5, 5.1, 5.12 are valid, but 5.123 is not)
Dangling dots are not allowed (5. is not valid)
Leading zeros are invalid (so 05.00 is invalid)

the regular expression can be

(^1?[0-9](\.[0-9]{1,2})?$)|(^20(\.0{1,2})?$)

edited Apr 13 '16 at 10:47

answered Apr 13 '16 at 10:20

Dmitry Bychenko

No 5 is also valid like it should handle both the scenario 5 & 5.00 or 5.89 etc – Bikram Sahu Apr 13 '16 at 10:23
1

@Bikram Sahu: But you've put "I require only **exactly 2 digits** after decimal point". So what about `5.1` is it a valid input? And what about `5.` (note the dot, please) – Dmitry Bychenko Apr 13 '16 at 10:27
Yes It is the valid input. Anyway Thanks for the quick response. – Bikram Sahu Apr 13 '16 at 11:01
`^(1?\d(?:\.\d{1,2})?|20(?:\.00?)?)$` would be a bit simpler don't you think? – Thomas Ayoub Apr 30 '16 at 14:44
@Thomas: `\d` allows *any* digit, including, say, Persian ones: `۰ ۱ ۲ ۳ ۴ ۵ ۶`; when `[0-9]` matches exactly `0..9` range – Dmitry Bychenko May 04 '16 at 06:30
OP never told us that he won't match Persian numbers... – Thomas Ayoub May 04 '16 at 13:39

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