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Return the object from the array with the highest value?

I am trying to return an object from an arraylist I have that contains different opponents for my text combat game. Opponents in an arraylist have different "deadlylevels" to separate one light opponent from a tough one.

Explain it differently; Let's say I have three opponents in my Arrayist and they have dead levels of 30, 40 and 50 respectively. I want to return the deadliest of them all, so it would be a dead level 50 enemy.

I already gave them different dead levels, but I'm not sure how to get the opponent with the highest dead level back.

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4 answers


Create Comparator

one that compares the levels of supporters and uses Collections.max(oponentList , theComparator)

.



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If you want the max level, it will just be max (). But you need a maximum level opponent. In Eclipse Collections we call this template maxBy()

. If you can replace ArrayList

with MutableList

, then it will look like this:

MutableList<Opponent> opponents = ...;
Opponent opponent = opponents.maxBy(Opponent::getDeadlyLevel);

If you cannot or will not convert ArrayList

, you can still use the static utility on Iterate

.

Opponent opponent = Iterate.maxBy(opponents, Opponent::getDeadlyLevel);

You can use Collections.max()

together with Comparator.comparing()

for assembly Comparator

.



Opponent opponent =
    Collections.max(opponents, Comparator.comparing(Opponent::getDeadlyLevel));

Or you can use Java 8 streams.

Optional<Opponent> optionalOpponent = 
    opponents.stream().max(Comparator.comparing(Opponent::getDeadlyLevel));
Opponent opponent = optionalOpponent.get(); // If you're sure there at least one

Note: I am a committer for Eclipse collections.

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Use Stream#max()

by providing a function for the corresponding attribute:

List<Fighter> list; // given a list of Fighters
Fighter deadliest = list.stream()
    .max((a,b) -> a.getDeadlyLevel() - b.getDeadlyLevel())
    .get();
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Use Comparator.comparing

import java.util.Arrays;
import java.util.Comparator;
import java.util.List;


public class DeathMatch {
    public static void main(String[] arg){
        List<Opponent> list = Arrays.asList(new Opponent("ZZ",10),new Opponent("WW",50),new Opponent("MM", 30));
        Opponent deadliest = list.stream().max(Comparator.comparing(p->p.getLevel())).get();
        System.out.println(deadliest.getName()+","+ deadliest.getLevel());
    }
}
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