Regex: How to match a string that contains repeated pattern?

Question

Is there a regex pattern that will match a string that contains repeated pattern, e.g.:

"a"|"b","c"|"d",...,"y"|"z"

Do you have any idea?

Answer 1

Just a note that to truly look for a repeated pattern, you can use grouping like so:

<(htmltag>).*\1

where \1 refers to the matched string in the 1st group repeated. Make sense?

Answer 2

Maybe you are looking for something like this:

^"."\|"."(,"."\|".")*$

This will match a comma-separated list of sequences of form "α"|"β" where α and β can be any character.