Regular expression for hyphen separated floating point numbers

Question

Need some help in designing regular expression to validate hyphen separated floating point numbers in Javascript. So far I have managed to achieve this RegEx:

(^((\\d)+(\.[0-9]+)?)(\-)?((\\d)+(\.[0-9]+)?)$)|^(\\d+)$

It matches the following:

1) 2
2) 2.10
3) 3.10-3.14

The problem with this one is that its also matching "3.103.310" which is wrong number. Much appreciate any help in fixing this issue.

Answer 1

The problem comes from the first alternative that matches 1 or more digits with an optional fractional part ( (\\d)+(\\.[0-9]+)? ) and then matches a hyphen and again 1+ digits and again an optional fractional part. Thus, 2 dots are allowed.

You may fix the pattern like this:

^\d+(?:\.\d+)?(?:-\d+(?:\.\d+)?)*$

See the regex demo

Details

• ^ - start of string
• \\d+ - 1+ digits
• (?:\\.\\d+)? - an optional non-capturing group:
  • \\. - a dot
  • \\d+ - 1+ digits
• (?:-\\d+(?:\\.\\d+)?)* - an non-capturing group matching 0+ occurrences of
  • - - a hyphen
  • \\d+(?:\\.\\d+)? - 1+ digits and 1 or 0 occurrences of . and 1+ digits
• $ - end of string