Need value in regex.match group

Question

I want to match regex such that the sign(+ or -) in one group and figure in other group. It may possible that figure comes without any sign(+ or -)

Example

 [-] 87.90
 [+] 87.78
 (-) 87.90
 (+) 87.78
  89
 -89.56
 - 89.98

I have used below regular expression

^\W*(\-|\+|)\W*(\d+(\.\d+)?)

By this I am getting empty in group 1 If I use

^\W*(\-|\+)\W*(\d+(\.\d+)?)

then 3rd figure will not match. So in short I want to match figure with (+ or -) or without any sign.

Answer 1

Group 1 is empty because the \\W* greedily matches all non-word characters, that is, all parentheses and signs.

You should specify the literal parentheses in the pattern and a character class will be a more natural construct to match either a + or a - :

(?:\(?([-+])\)?)?\p{Zs}*(\d+(\.\d+)?)

See regex demo (if you need a full string match, use ^ at the start and $ at the end of the pattern).

Regex matches:

• (?:\\(?([-+])\\)?)? - an optional non-capturing group ( (?:...) ) that matches a ( optionally, followed by a plus or minus (Group 1), and then by an optional )
• \\p{Zs}* - zero or more whitespace symbols
• (\\d+(\\.\\d+)?) - (Group 2) one or more digits followed by an optional capturing group (Group 3) that matches a period followed by one or more digits.

Result: