Printing a list in alphabetical order with letter headings

Question

I have a list of strings in alphabetical order I want to print, but I want to do so with corresponding letter headings. For example:

["Blue","Cat in hat","Zebra","2 Words"]

## B
    Blue
## C
    Cat in hat
## Z
   Zebra
## [0-9]
   2 Words

Whats the best way to do this? It should be case insensitive, so "hello" and "Hello" both go under H.

Answer 1

This would help you:

Note: Assuming the list is sorted.Otherwise you need to do sort first.

for (String str : stringList) {

    if (Character.isDigit(str.charAt(0))) {
        if (!Character.isDigit(previousChar)) {
        System.out.println("## [0-9]");
        }
    } else if (Character.toUpperCase(str.charAt(0)) != previousChar) {

        System.out.println("## " + Character.toUpperCase(str.charAt(0)));
    }

    previousChar = Character.toUpperCase(str.charAt(0));

    System.out.println(str);
}