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?

+1 on examples. Do you mean "any repeated pattern" or the specific pattern you mentioned? Give some examples and counter-examples. — Jason Cohen
– Jason Cohen, Commented Mar 15, 2009 at 17:17

Gumbo · Accepted Answer · 2009-03-15 17:46:17Z

4

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.

answered Mar 15, 2009 at 17:30

Gumbo

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3 Comments

Thanks, but it still match "a"|"b","c"|"d",aaa or "a"|"b","c"|"d", Can u fix it? Plz

I’ve added anchors for the start and the end of the string ^…$.

@Gumbo: I am sure that "u can fix it". ;-) Deleting my answer, +1 for you.

Eric Wendelin · Accepted Answer · 2009-03-15 18:06:26Z

2

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?

answered Mar 15, 2009 at 18:06

Eric Wendelin

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Yes, it makes sense and it should be marked as the more correct answer.