Modify a 4 digit number inside of a string and inserting colon

I have a string and i want to modify all 4 digit numbers and inserting colon between. Example: 1320 will become 13:20

$data = "The time is 1020 and the time is 1340 and 1550";

I'm thinking to use preg_match('/[0-9]{4}/', '????', $data);

But not sure how to pass the same value again in the preg?

Solution

One way could be to use preg_replace instead and use capturing groups to capture 2 times 2 digits (\d{2})(\d{2}) between word boundaries \b

In the replacement use the 2 capturing groups using $1:$2

$data = "The time is 1020 and the time is 1340 and 1550";
$data = preg_replace('/\b(\d{2})(\d{2})\b/', "$1:$2", $data);
echo $data;

Result:

The time is 10:20 and the time is 13:40 and 15:50