Qfyilyi

I have strings in a list and through only using the stream api I was settings all strings to lowercase, sorting them from smallest string to largest and printing them. The issue I'm having is capitalizing the first letter of the string. Is that something I do through .stream().map()?

Main:

public static void main(String args) {



    List<String> list = Arrays.asList("SOmE", "StriNgs", "fRom", "mE", "To", "yOU");

    list.stream().map(n -> n.toLowerCase())

        .sorted((a, b) -> a.length() - b.length())

        .forEach(n -> System.out.println(n));;



}

Output:

me

to

you

some

from

strings

Desired output:

Me

To

You

Some

From

Strings

Something like this should suffice:

 list.stream()

     .map(n -> n.toLowerCase())

     .sorted(Comparator.comparingInt(String::length))

     .map(s -> Character.toUpperCase(s.charAt(0)) + s.substring(1))

     .forEach(n -> System.out.println(n));

1. note that I've changed the comparator, which is essentially the idiomatic approach to do it.


2. I've added a map operation after sorting to uppercase the first letter.

list.stream()

    .map(s -> s.substring(0, 1).toUpperCase() + s.substring(1).toLowerCase())

    .sorted(Comparator.comparingInt(String::length))

    .forEach(System.out::println);

For readability, the line performing capitalisation should be moved into a method,

public class StringUtils {

    public static String capitalise(String s) {

        return s.substring(0, 1).toUpperCase() + s.substring(1).toLowerCase();

    }

}

so you can refer to it via an eloquent method reference:

list.stream()

    .map(StringUtils::capitalise)

    .sorted(Comparator.comparingInt(String::length))

    .forEach(System.out::println);

You can use WordUtils::capitalizeFully from apache commons-lang for this.

 list.stream()

     .sorted(Comparator.comparingInt(String::length))

     .map(WordUtils::capitalizeFully)

     .forEach(System.out::println);