Get first number in a string after the first occurrence of identifier

Question

I\'m working on a function that gets a string like this:

identifier 20 j. - cat: text text text aaaa ffffdd ..... cccc 60\' - text, 2008

and

Answer 1

You can use a regular expression for this:

$matches = array();
preg_match('/identifier\s*(\d+)/', $string, $matches);
var_dump($matches);

\s* is whitespace. (\d+) matches a number.

You can wrap it in a function:

function matchIdentifier($string) {
    $matches = array();
    if (!preg_match('/identifier\s*(\d+)/', $string, $matches)) {
        return null;
    }
    return $matches[1];
}

Answer 2

You can get the match itslef without capturing subgroups using \K operator and ^ anchor to match the word only at the beginning of the string:

$re = "/^identifier \\K\\d+/"; 
$str = "identifier 20 j. - cat: text text text aaaa ffffdd ..... cccc 60' - text, 2008"; 
preg_match($re, $str, $matches);
echo $matches[0];

Demo is here.

Sample program is available here (PHP v5.5.18).

Answer 3

$string = "identifier 20 j. - cat: text text text aaaa ffffdd ..... cccc 60' - text, 2008";
$tokens = explode(' ', $string);
$token2 = $tokens[1];
if(is_numeric($token2))
{
    $value = (int) $token2;
}
else
{
    $value = NULL;
}