Match floats in Ruby with regexp

Question

I need to extract a float from a string in Ruby, but if I try to extract it with the normal \d I of course don't fetch the digits in front of the ",".

"3,25 år -".match((\d+)\s?år\s?-)[1] => # "25"

Is there an easy way to fetch the whole number?

score 2 · Accepted Answer · answered Dec 01 '13 at 15:54

2

"3,25 år -".match(/([\d,]+)\s?år\s?-/)[1] => # "3,25"

Pay attention that your code also had another error. You were missing the regex delimiters. It should be

match(/.../)

not

match(...)

answered Dec 01 '13 at 15:54

Simone Carletti

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Thanks @psxls. Also thanks for pointing me to the Scuba Diving proposal. I'm a Scuba Instructor, I've added the proposal to my profile, it may help to advertise it a little bit. – Simone Carletti Dec 01 '13 at 16:21

score 0 · Answer 2 · edited May 23 '17 at 12:28

You are missing the forward slashes / around the regular expression.

Apart of that, this will return what you want:

"3,25 år -".match(/(\d+(?:,\d+)?)\s?år\s?-/)[1] => # "3,25"

As a side note, the above will match both positive integers and floats. If you are sure you will always have floats, simplify it like that:

"3,25 år -".match(/(\d+,\d+)\s?år\s?-/)[1] => # "3,25"

Finally, I would propose you to get used to the [0-9] notation for digits instead of \d, ready why here, so finally try this:

"3,25 år -".match(/([0-9]+,[0-9]+)\s?år\s?-/)[1] => # "3,25"

PS. I would suggest you to avoid the [\d,]+ solutions since this regular expression can match also non-numbers, eg it will match 1,,1 or 1, or ,1.

Match floats in Ruby with regexp

2 Answers2