What is regex for abc4 and abc20 in JavaScript?

Question

I need a regular expression to match two words, "abc4" and "abc20".

My solution is abc[4,20]. This does not work.

Here is an answer that goes a little more in depth on this issue https://stackoverflow.com/questions/8020848/and-or-operator-in-regular-expression — ballmerspeak, Feb 09 '18 at 16:25
Visual explaination on why yours did not work: https://regexper.com/#%2Fabc%5B4%2C20%5D%2F — epascarello, Feb 09 '18 at 16:27
`[]` creates a character class that says *match any **character** in this class*. In your case, `[4,20]` will either match `4`, `,`, `2`, or `0`. You need to use the or `|` operator **outside** a character class as such: `(?:4|20)` — ctwheels, Feb 09 '18 at 16:30
Check out this [fiddle](https://jsfiddle.net/jfd1yoL2/1/). If the question gets re-opened, I'll post it as an answer, but basically it's a function that will build a regex like: `/(part1[0])(part2[0]|part2[1])/g`. You simply provide it with the string you want to test against, and 2 arrays of parts to match, and it'll run. As you've simplified the question, this may be better suited to answer it. Note, that it probably wont play nice with regex special characters though, that may require a bit of editing — KyleFairns, Feb 09 '18 at 17:35

score 3 · Answer 1 · edited Feb 09 '18 at 16:35

Please, try this one: /^abc(4|20)$/

let regExp = /^abc(4|20)$/

let strings = document.querySelectorAll(".example");

for (let string of strings) {
  if (string.innerHTML.match(regExp)) {
    string.style.background = "tomato";
  }
}

<div class="example">abc4</div>
<div class="example">4abc</div>
<div class="example">abc20</div>
<div class="example">bbb4</div>
<div class="example">abc20</div>
<div class="example">erw32</div>
<div class="example">abc4</div>
<div class="example">abc20</div>
<div class="example">turnip</div>

See online demo

What is regex for abc4 and abc20 in JavaScript?

1 Answers1