How to parse a 1 or 2 digit hour string with Java?

Question

My parser may encounter \"2:37PM\" (parsed by \"H:mma\") or \"02:37PM\" (parsed by \"hh:mma\"). How can I parse both without resorting to a try-catch?

I receive an erro

Answer 1

You can use String#format with %02d on the hour portion of the String. This will pad the value with 0 until its size 2. We can then replace the original hour portion with the formatted portion.

        String timeLiteral = "2:37PM";

        String originalHour = timeLiteral.split(":")[0];

        String formattedHour = String.format("%02d", Integer.parseInt(originalHour));

        String result = timeLiteral.replace(originalHour, formattedHour);