PHP extract ID from a string

Question

Eg: Lorem ipsum dolor sit amet, [ID: 123] Suspendisse [blahsh 68] condimentu

How would I get 123?

I have the first part where I check the character position:

$pos = strrpos($l, "ID: ");
if ($pos === false) {
    $id = 123;
}

Answer 1

This is most easily handled with a regular expression.

$matches = array();
$pattern = '/^.*\[ID:\s+(\d+)\].*$/';
preg_match($pattern, "Lorem ipsum dolor sit amet, [ID: 123] Suspendisse [blahsh 68] condimentu", $matches);


// Your number is in $matches[1]
Array
(
    [0] => Lorem ipsum dolor sit amet, [ID: 123] Suspendisse [blahsh 68] condimentu
    [1] => 123
)

The pattern matches [ID: followed by any number of spaces via \\s+ . Then (\\d+) captures the sequence of digits. The [] brackets need to be escaped as \\[ \\] because they are meta-characters in the regular expression.

If you are interested in the rest of the expression:

• ^.* is the start of the string and anything else following...
• .*$ is anything else up to the end of the string after the matched section already explained above.

Answer 2

Maybe like this if the string is always [ID:1234]

$str='Lorem ipsum dolor sit amet, [ID: 123] Suspendisse [blahsh 68] condimentu';
preg_match_all("~\[ID:\s(.*?\d+)\]~",$str,$match);
echo $match[1][0];