Regex Expression for words between two punctuation

Question

How can I make this regex expression find every string in my text that matches this format, I tried adding the curly braces but it only find the first word in the format and when removed it find every word.

My regex expression: {((?:[a-z][a-z0-9_]*))
My text: {Hello|Hi|Hey} John, How are you? I'm fine

Answer 1

To get all the matches between curly brackets, you could match from { till } and capture what is in between in a capturing group.

Then use explode and use | as a delimiter. If you have multiple results you could loop the results:

$str = "My text: {Hello|Hi|Hey} John, How are you? I'm fine";
preg_match_all('~{([^}]+)}~', $str, $matches);

foreach($matches[1] as $match) {
    print_r(explode('|', $match));
}

Result

Array
(
    [0] => Hello
    [1] => Hi
    [2] => Hey
)

Php demo

Another option could be to make use of the \G anchor:

(?:\G(?!\A)|{(?=[^{}]*?}))([^|{}]+)[|}]

Explanation

• (?: Non capturing group
  • \G(?!\A) End of the previous match but not at the start
  • | Or
  • {(?=[^{}]*?}) Match { and assert what follows contains not } and then }
• ) Close non capturing group
• ([^|{}]+) Capture in a group matching NOT what is listed in the character class
• [|}] Match what is listed in the character class

php demo

Answer 2

You can use this look around based regex that will give you all the matches in curly brackets,

(?<=[{|])\w+(?=[|}])

Demo

Try this Python code,

$s = "{Hello|Hi|Hey} John, How are you? I'm fine";
preg_match_all('/(?<=[{|])\w+(?=[|}])/',$s,$matches);
print_r($matches);

Array
(
    [0] => Array
        (
            [0] => Hello
            [1] => Hi
            [2] => Hey
        )

)

Online PHP demo