Simplify & Fix Regex

Question

I'm new to working with regular expressions and was wondering if the following regex could somehow be simplified...

{{(?:[\s]+)?(.*)([\s]+)?}}

I am trying to get the string out of the following pattern...

{{SOME_STRING}}
{{    SOME_STRING}}
{{  SOME_STRING   }}
{{  SOME-STRING      }}
{{  SomE STRING  }}

Additionally, it doesn't quite work right as there should not be any trailing spaces on the match.

Regex101 Link: http://regex101.com/r/kT9yT5

Answer 1

there should not be any trailing spaces on the match

You can try below regex and get the matched group

/{{\s*(.*?)\s*}}/g

that means every thing that is enclosed inside {{ and }} are grouped using Reluctant quantifiers.

Here is Online Demo

Read more about Greedy vs. Reluctant vs. Possessive Quantifiers

Answer 2

For A Direct Match, use \K Magic

{{\s*\K[^}]+?(?=\s*}})

See demo.

Explanation

• {{\s* matches the opening braces and any whitespace characters
• The \K tells the engine to drop what was matched so far from the final match it returns
• The negated character class [^}]+? lazily matches any characters up to...
• The point where the lookahead (?=\s*}}) can assert that what follows is spaces and the closing braces.

Sample Code

See the output at the bottom of the live php demo.

$regex = '~{{\s*\K[^}]+?(?=\s*}})~';
preg_match_all($regex, $yourstring, $matches);
print_r($matches[0]);

Output

[0] => SOME_STRING
[1] => SOME_STRING
[2] => SOME_STRING
[3] => SOME-STRING
[4] => SomE STRING

Answer 3

You could try the below regex to remove all the trailing and beginning white spaces present inside the {},

\{\{\s*(\w+[-\s]?\w+)\s*\}\}

DEMO

Explanation:

• \{\{ Literal opening curly braces {{
• \s* zero or more spaces.
• \w+ One or more word characters.
• [-\s]? Optional - or space character.
• \w+ One or more word characters.
• \s* Zero or more space characters.
• \}\} Literal closing curly braces }}

You code would be,

$regex = '~\{\{\s*(\w+[-\s]?\w+)\s*\}\}~';
preg_match_all($regex, $yourstring, $matches);
print_r($matches[1]);

Ideone