仅使用preg_replace替换preg字符串的最后一个匹配项？

Question

just the the images

$content="}
}
hello world
          }
}"
$text='}\s*[
]*\s*[
]*\s*}';
$ss="~$text(?!.*$text)~";
$res=preg_replace($ss,'replacement',content);
echo $res;//$res:"replacement hello world replacement"

I want replace only the last '} }'using preg_replace()

Answer 1

You can replace the last to occurrences of } with only whitespace chars between them using:

}\s*}(?![^}]*})$

• }\s*} Match }, 0+ whitespace chars, then }
• (?![^}]*}) Negative lookahead, assert what is on the right are no more occurrences of ]
• $ Assert end of the string

Note that this does not take balances parenthesis into account, just the last to }

Regex demo