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Java Java Arrays Gotchas and Wins Sorting

Posted by john DOe
john DOe
27,897 Points

How do I compare by multiple things, such as length first and then the normal lexical string compare?

So, if I want to sort multiple strings, and many of them all have the same length, then I want them to be sorted alphabetically; how do I do that?

1 Answer

Michael Leshowitz
Michael Leshowitz
1,728 Points
Michael Leshowitz
Michael Leshowitz
1,728 Points

Hey Oindril! I was curious about this too. It looks like Java 8 added the thenComparing() method to the Comparator class. If you wanted to sort an array by length of strings and then alphabetically, you could use the following sort call: (say we're working with the friends array described in this lesson)

Arrays.sort(friends, Comparator.comparing(String::length).thenComparing(String::compareTo))

This thenComparing() method takes the same input as the comparing() method. Further, you can add these thenComparing() calls ad nauseam.

Arrays.sort(ARRAY, Comparator.comparing(FIRST).thenComparing(SECOND).thenComparing(Third)...)

If you're working on an earlier version, I've seen post about creating a custom Comparator classes, but that's more advanced than this course.

Hope this helps!