More compact RegEx for capturing one or more groups with delimiters - without repeating the group expression

Asked Feb 22 '19 at 12:37

Active Feb 22 '19 at 16:34

Viewed 14 times

This occurs so frequently in validation RegExps I was wondering whether there was a more efficient form that I'm missing.

Consider the following RegExp: ^[\w\s-&’'!À-Üà-øoù-ÿŒœ]+(\|[\w\s-&’'!À-Üà-øoù-ÿŒœ]+)*$

All it's doing is validating all of the following:

l'écureuil
losange|l'hibou|Œdeppe

What is frustrating me is that I must repeat the entire capture class twice, just so I can handle the cases of a single entry (with no leading delimiter), and then cases where there are multiple groups separated by the (required) delimiter

\1 doesn't work here of course because I'm not matching the same string.

(this question is not about how I can capture French words using a more succinct class definition - that's just an arbitrary example)

edited Feb 22 '19 at 16:34

asked Feb 22 '19 at 12:37

Tom Auger

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Use [subroutines](https://www.regular-expressions.info/subroutine.html). – Wiktor Stribiżew Feb 22 '19 at 12:38
Note that the `|` in your expression does not match an actual `|` character. `|` in regex means "or". – Jerry Feb 22 '19 at 12:43
Thanks @Jerry- edited. – Tom Auger Feb 22 '19 at 16:34
The duplicated question ist a working, but my Idea was to only Check, If The First character is a delimiter Like `^[^\|]([\|\w\s-&’'!À-Üà-øoù-ÿŒœ]+)*$` – D-E-N Feb 22 '19 at 20:10

More compact RegEx for capturing one or more groups with delimiters - without repeating the group expression

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