Sorting strings using Ordered[String] in Scala?

Question

I need to have an equivalent of the compareWith(a,b) method in Java, in Scala.

I have a list of strings and I need to sort them by comparing them with each other. sortBy just takes one string and returns a score, but that's not enough in my case, i need to compare two strings with each other and then return a number based on which one is better.

It seems like the only option is to write a custom case class, convert the strings to it, and then covert them back. For performance reasons, I want to avoid this as I have a large amount of data to process.

Is there a way to do this with just the strings?

compareWith()? I'm having a hard time finding the documentation for that. Can you provide a link? Also, I'm not sure what's wrong with "abc" compareTo "xyz". Please clarify. — jwvh
– jwvh, Commented Sep 12, 2018 at 6:15
It was compareTo rather than with, I haven't used java in a while. And what's wrong is that I need to write my own rules for the comparison. — Ali
– Ali, Commented Sep 12, 2018 at 14:49
Ah, that explains why I couldn't find it. As for compareTo(), I guess I still don't understand your objections and/or requirements. When it comes to sorting a List[String], you can .sortWith(_.compareTo(_)<0) (which you seem to like), or you can .sortBy(s=>s) (which is shorter), or you can .sorted (which is direct and to the point). — jwvh
– jwvh, Commented Sep 12, 2018 at 15:31

Community · Accepted Answer · 2020-06-20 09:12:55Z

7

I think you are looking for sortWith.

sortWith(lt: (A, A) ⇒ Boolean): Repr

Sorts this sequence according to a comparison function.

Note: will not terminate for infinite-sized collections.

The sort is stable. That is, elements that are equal (as determined by lt) appear in the same order in the sorted sequence as in the original.

　lt the comparison function which tests whether its first argument precedes its second argument in the desired ordering.

Example:

List("Steve", "Tom", "John", "Bob").sortWith(_.compareTo(_) < 0) =
List("Bob", "John", "Steve", "Tom")

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Sep 12, 2018 at 6:05

Thilo

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Comments

Marto · Accepted Answer · 2023-08-09 20:17:43Z

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I think .sorted will do the trick.

answered Aug 9, 2023 at 20:17

Marto

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