Regexp for nine letters separated by '/'

Question

I need to write a regex that will allow 9 numbers and/or digits to be written in such format: XXX/XXX/XXX. However, the amount of them in each can vary, so for example it can be like: XX/XXXX/XXX as long as there are max 4 x's.

Tried my best but didn't come up with any solution.

Can you share what you have tried? – The fourth bird Mar 13 '18 at 16:15 — The fourth bird, Mar 13 '18 at 16:15

score 1 · Answer 1 · answered Mar 13 '18 at 16:21

JavaScript based solution:

var input = prompt("Enter something");

var isValid = false;

if(/^\d{1,4}\/\d{1,4}\/\d{1,4}$/.test(input) && input.replace(/\//g, "").length == 9) {
  isValid = true;
}

console.log("Valid: ", isValid);

Explanation:

\d denotes digits.
Forward Slash / is a special character, hence it needs to be escaped, like \/
You specify range with {0,4}
After the pattern is verified, you have to strip out all the / from the input, and then compare length with 9

score 1 · Answer 2 · answered Mar 13 '18 at 16:35

1

REGEX ONLY

(?=\b.{11}\b)[0-9]{1,4}\/[0-9]{1,4}\/[0-9]{1,4}

(?=\b.{11}\b) a positive lookahead asserting that you have exactly 11 char (because you have 9 digits and 2 slashes)
[0-9]{1,4} a group of minimum 1 and maximum 4 digits (you can use \d instead of 0-9)
\/ a slash escaped

Live demo here.

Don't forget to turn the g option on, which means that you don't return after the first match.

answered Mar 13 '18 at 16:35

Francesco B.

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Wish I thought of using Regex101 site, good choice, and the Positive Look-ahead, is a better approach. – Abhijit Kar ツ Mar 13 '18 at 16:44

Regexp for nine letters separated by '/'

2 Answers2