Can you use backlinks in the regex pattern part?

Question

Is there a way to backlink in a regex pattern?

Example input line:

Here is "some quoted" text.

Say I want to pull out the quoted text, I could create the following expression:

"([^"]+)"

This regular expression will match some quoted.

Say I want it to support single quotes, I could change the expression to:

["']([^"']+)["']

But what if the input string contains a mixture of quotes, say Here is 'some quoted" text., I would not want the regular expression to match. Currently, the regex in the second example will still match.

, , , - , . - , .

?

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Answer 1

:

(["'])[^"']+\1

• ():
• [..]: char. ["'] ", ' "|'
• [^..]: char . char, ^
• +:
• \1: , (["'])

PHP :

preg_match('#(["\'])[^"\']+\1#',$str)

Answer 2

preg_match('/(["\'])([^"\']+)\1/', 'Here is \'quoted text" some quoted text.');

: (["'])([^"']+)\1/ . , 1. , , \1, , 1.

Answer 3

/"\(.*?\)".*?\1/ ,