Extract number from string with regex in groovy

Question

I have the following type of strings with numbers within:

(12  -   17)
(4.5  - 5.5)
(4    -  10)

My code which works for the first two examples is like this:

def numbers=range=~/\d{1,3}.?\d{1,2}?/

where the result for numbers is :

[12,17]
[4.5,5.5]

but for the last is only [10] it does not get the 4 .

Does anyone see where I am wrong?

Answer 1

Your regex requires at least 2 integer digits on end. Look: \\d{1,3} matches 1 to 3 digits, .? matches any character but a newline 1 or 0 times (optional) and \\d{1,2}? matches 1 or 2 digits (the {1,2}? is a lazy version of a limiting quantifier meaning it will match as few digits as possible to return a valid match).

Use

/\d{1,3}(?:\.\d{1,2})?/

See the regex demo .

Explanation :

• \\d{1,3} - 1 to 3 digits
• (?:\\.\\d{1,2})? - 1 or 0 sequences (due to ? ) of:
  • \\. - a literal period
  • \\d{1,2} - 2 or 1 digits (this is a greedy version of the limiting quantifier).

Here is a Groovy demo :

def x = "(12  -   17)(4.5  - 5.5)(4    -  10)"
def res = x.findAll(/\d{1,3}(?:\.\d{1,2})?/)
println res

Output: [12, 17, 4.5, 5.5, 4, 10]