Question

I want to be able to validate the strings below to allow data between backticks unlimited times as long as it is followed by a comma, if it is not a comma must be a “)”. Whitespaces are allowed only out of the backticks not in them.

I am not experienced with regex so I dont know how to allow a repeated pattern. Below is my pattern so far.

Thanks

UPDATED

// first 3 lines should match
$lines[] = "(`a-z0-9_-`,`a-z0-9_-`,`a-z0-9_-`,`a-z0-9_-`)";
$lines[] = "( `a-z0-9_-`, `a-z0-9_-` ,`a-z0-9_-` , `a-z0-9_-` )";
$lines[] = "(`a-z0-9_-`, 
    `a-z0-9_-` 
    ,`a-z0-9_-` ,`a-z0-9_-`)";

// these lines below should not match
$lines[] = "(`a-z0-9_-``a-z0-9_-`,`a-z0-9_-`,`a-z0-9_-`)";
$lines[] = "(`a-z0-9_-``a-z0-9_-`,`a-z0-9_-`.`a-z0-9_-`";

$pattern = '/~^\(\s*(?:[a-z0-9_-]+\s*,?\s*)+\)$~/';

$result = array();

foreach($lines as $key => $line)
{
        if (preg_match($pattern, $line))
        {
            $result[$key] = 'Found match.';
        }
        else
        {
            $result[$key] = 'Not found a match.';
        }
}

print("<pre>" . print_r($result, true). "</pre>");

Answer 1

Well you weren’t very clear about the matching rules for the data between the brackets, and you didn’t really specify if you wanted to capture anything so…I took a best guess based on context of your code, hopefully this will suit your needs.

edit: fixed code block so it would show the backtics in the pattern, also changed the delimiter from ~ to / since OP was confused about that

$pattern = '/^\((\s*`[a-z0-9_-]+`\s*[,)])+$/';