CODEWITHSUNDEEP
rubyregex
Jack
Jack

Reputation: 497

Ruby regex specify length of captured group

I need to match a string of variable length(between 5 and 12), composed of uppercase letters and one or more digits between 1 and 8. How can I specify that I need the whole captured group's length to be between 5 and 12? I have tried with parenthesis but with no luck. I have tried this

\s([A-Z]+[1-8]+[A-Z]+){5,12}\s

My idea was to use the quantifier {5,12} to limit the length of the captured group between parenthesis, but clearly it doesn't work like that.

The string needs to be identified inside a normal text just like 

"THE STRING I NEED TO DECODE IS SOMETHING LIKE FD1531FHHKWF BUT NOT LIKE g4G58234JJ"

Upvotes: 0

Views: 2505

Answers (2)

Arun
Arun

Reputation: 915

Use positive look-ahead on total size of regex 

\s(?=^.{5,12}$)([A-Z]+[1-8]+[A-Z]+)\s

Explanation

(?=        # look-ahead match start
^.{5,12}$  # 3 to 15 characters from start to end
)          # look-ahead match end

Upvotes: 2

Aleksei Matiushkin
Aleksei Matiushkin

Reputation: 121000

You actually have two conditions to met:

The length of the match is to be specified with curly brackets {5,12}, and before and after there should be not letters/digits. So:

/(?!\b[A-Z]+\b)\b[A-Z1-8]{5,12}\b/

First, we assure that the lookahead for letters only is negative, then we look for the pattern.

Upvotes: 2

Related Questions