使用正则表达式从文本中只找到双花括号单词

Question

I have a text like this

Hello {{xyz}} how are {{abc}. I am {opq}} for your {{bpq}}.

from this text i want to find only {{abc} and {opq}} except {{xyz}} and {{bpq}} . what will be the regular expression for php .

I have tried this

preg_match_all("/\{{(.*?)\}}/", $mytext, $matches);

Answer 1

You can use this regex in PHP with PCRE verb (*SKIP)(*F) which is used to skip+fail a match in alternation.

{{[^{}]*}}(*SKIP)(*F)|{{[^{}]*}|{[^{}]*}}

RegEx Demo

Alternatively , you can also use a lookaround based regex:

{{[^{}]*}(?!})|(?<!{){[^{}]*}}

• (?!}) is negative lookahead to fail the match if next char is }
• (?<!}) is negative lookbehind to fail the match if previous char is {