匹配正则表达式不起作用

Question

I have a string $subDay like this:

Checkin 03:35 OL 270 DRS-ZRH 04:25-05:45 HSC, KRG, LEM, JOA OL 271 ZRH-DRS 06:45-08:15 HSC, KRG, LEM, JOA Checkout 08:45

and I want to add a new line ( ) with this command:

$subDay = preg_replace("/(Checkin [12][0-9]:[12][0-9])/", "$1
", $subDay);

I tested it with this RegexTester and my RegEx seems valid, but nothing happens.

Why?

Answer 1

Finally i used this RegEx:

/(Checkin ([01]{1}[0-9]{1}|[2]{1}[0-3]):[0-5]{1}[0-9]{1})/

It only matches double-digit valid times.