Question

Consider the following string:

LoReM {FOO} IPSUM dolor {BAR} Samet {fooBar}

I’m looking for a way to lowercase everything – except what is between {brackets} should be ignored. So the desired output is:

lorem {FOO} ipsum dolor {BAR} samet {fooBar}

In another topic @stema pointed to https://www.php.net/manual/en/functions.anonymous.php to achieve something like this, but I dont understand how:

echo preg_replace_callback('~\{.*?\}~', function ($match) {
  return strtolower($match[1]);
}, 'LoReM {FOO} IPSUM dolor {BAR} Samet {fooBar}');

This returns only the string without the bracketed {tags}, and not even lowercased. Who can help me solve this? Any help is greatly appreciated 🙂

Answer 1

Change your regex to:

~(?:^|})(.*?)(?:\{|$)~

explanation:

~           : delimiter
  (?:       : start non capture group
    ^|}     : begin of string or }
  )         : end of group
  (         : start capture group #1
    .*?     : any number of any char. non greedy
              (ie: all char outside of {})
  )         : end of group
  (?:       : start non capture group
    \{|$    : { or end of string
  )         : end of group
~           : delimiter