使用正则表达式从字符串返回第一个外部结果

Question

I have the following string:

"{My {formatted {hi|hello}|formate{hi|hello} }  {option 1|option 2|option 3}}";

I want find the result in-between the "{" and "}" brackets.

Also result should be from the outer layer, not {hi|hello} but:

"My {formatted {hi|hello}|formate{hi|hello} }  {option 1|option 2|option 3}"

Answer 1

You can extract the most outer content from an indeterminate level number of nested brackets with this pattern:

$pattern = '~{((?>[^{}]++|(?R))+)}~';

where (?R) means repeat the whole pattern . It is a recursive approach.
If you need the same to use as subpattern in a larger expression, you must use:
({((?>[^{}]++|(?-2))+)}) since the (?-2) is a relative reference to the second capturing group on the left (the first here).

Pattern details:

 (             # first capturing group
   {           # literal {
   (           # second capturing group (what you are looking for)
     (?>       # atomic group
       [^{}]++ # all characters except { and }, one or more time
      |        # OR
       (?-2)   # repeat the first capturing group (second on the left)
     )+        # close the atomic group, repeated 1 or more time
   )           # close the second capturing group
   }           # literal }
 )             # close the first capturing group

Answer 2

/^{(.*)}$/ would remove the first and last { and }

used via $var = preg_replace('/^{(.*)}$/', '$1', $your_text);

That particularly can be made with basic string operations too, you could advance that regex to /^[^{]*{(.*)}[^{]*$/ which would let you put chars in front of the desired string and after it. Again, this can be done with string operations itself, using substr and strrpos .

Answer 3

I think you can use the split Function.E then you can use the Replace .

http://php.net/manual/pt_BR/function.split.php