I'm trying to do a match and replace of strings that follow these patterns:

text_text_text
text_text
text_123

Basically, alphanumeric and one or more underscores.

The replace will basically just take the match and add a bold tag to it.

I have this so far but it matches basically with most of the text in my content:

$description = preg_replace(
"~[[:alnum:] _] ~",
"<b>\\0<\b>",
$description);

Any help is appreciated.

CodePudding user response：

If you only want to match when there's at least one underscore, you have to make that a required character, not part of the character set.

$description = preg_replace('~([[:alnum:]] _) [[:alnum:]] ~', '<b>$0</b>', $description);

CodePudding user response：

Try the following and see if it meets your requirements:

$description = preg_replace(
  '~(?:[[:alnum:]] )(?:_[[:alnum:]] ) ~', 
  '<b>$0</b>', 
  $description
);

Explanation:

• ~ delimiter

  • (?: start of non-capturing group

    • [ start character class
      • [:alnum:] match alphanumeric characters
    • ] end character class
    • match character class 1 or more times

  • ) end non-capturing group

  • (?: start of non-capturing group

    • _ match underscore
    • [ start character class
      • [:alnum:] match alphanumeric characters
    • ] end character class
    • match character class 1 or more times

  • ) end non-capturing group

  • match non-capturing group 1 or more times

• ~ delimiter

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