Java Scanner useDelimiter() Method

Question

scanner.useDelimiter("\.|(?<=\d{2})");
    System.out.print("Enter dms: ");
    degrees = scanner.next();
    minutes = scanner.next();
    seconds = scanner.next();

An input of 36.5212 returns seconds = 1, not seconds = 12. How would I correct my scanner.useDelimeter method? Thank you!

Progman · Answer

The problem is that the regex .|(?<=d{2}) is matching the position between the 1 and the 2, because at the position 36.521|2 (current position indicated by the | character), there are two digits to the left (the string 21).
You can change the regex to the following:
.|(?<=.d{2})

This way you enforce it, that the valid positions are only the . character itself or the position 36.52|12, where there is the positive look-behind of .dd (the string .52). The position 36.521|2 will not match anymore because the . character is missing between 5 and 2.
You can check the issue with your regex with the visualization from https://regex101.com/r/fL3kyA/1:

As you see by the pink bars, it finds three positions, even though you only want one.

Java Scanner useDelimiter() Method

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