Regex: Last Occurrence of a Repeating Character

Question

So, I am looking for a Regex that is able to match with every maximal non-empty substring of consonants followed by a maximal non-empty substring of vowels in a String

e.g. In the following strings, you can see all expected matches:

"zcdbadaerfe" = {"zcdba", "dae", "rfe"}

"foubsyudba" = {"fou", "bsyu", "dba"}

I am very close! This is the regex I have managed to come up with so far:

([^aeiou].*?[aeiou])+

It returns the expected matches except for it only returns the first of any repeating lengths of vowels, for example:

String: "cccaaabbee"

Expected Matches: {"cccaaa", "bbee"}

Actual Matches: {"ccca", "bbe"}

I want to figure out how I can include the last found vowel character that comes before (a) a constant or (b) the end of the string.

Thanks! :-)

It looks like you wanted to write [`[^aeiou].*?[aeiou]+`](https://regex101.com/r/HG85Is/1) — bobble bubble, Oct 08 '22 at 08:05

score 3 · Answer 1 · answered Oct 08 '22 at 03:42

3

Your pattern is slightly off. I suggest using this version:

[b-df-hj-np-tv-z]+[aeiou]+

This pattern says to match:

[b-df-hj-np-tv-z]+ a lowercase non vowel, one or more times
[aeiou]+ followed by a lowercase vowel, one or more times

Here is a working demo.

answered Oct 08 '22 at 03:42

Tim Biegeleisen

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Class ranges of course, that's slick.+1 – zer00ne Oct 08 '22 at 04:19

zer00ne · Accepted Answer · 2022-10-08T04:10:27.370

const rgx = /[^aeiou]+[aeiou]+(?=[^aeiou])|.*[aeiou](?=\b)/g;

Segment	Description
`[^aeiou]+`	one or more of anything BUT vowels
`[aeiou]+`	one or more vowels
`(?=[^aeiou])`	will be a match if it is followed by anything BUT a vowel
`\|`	OR
`.*[aeiou](?=\b)`	zero or more of any character followed by a vowel and it needs to be followed by a non-word

function lastVowel(str) {
  const rgx = /[^aeiou]+[aeiou]+(?=[^aeiou])|.*[aeiou](?=\b)/g;
  return [...str.matchAll(rgx)].flat();
}

const str1 = "cccaaabbee";
const str2 = "zcdbadaerfe";
const str3 = "foubsyudba";

console.log(lastVowel(str1));
console.log(lastVowel(str2));
console.log(lastVowel(str3));

Regex: Last Occurrence of a Repeating Character

2 Answers2