I have ArrayList zombie, which is populated with an object called Zombie. Zombie has the attributes health, x, y. How would I sort the array in ascending order, using the attribute x of Zombie, which is set to initially have random values?
I have already found a possible solution to my problem, but I do not understand the syntax of the answer. Explaining that answer may help, also.
You want to use Collections.sort in conjunction with a custom Comparator.
Collections.sort(list, new Comparator<Zombie>() {
@Override
public int compare(Zombie z1, Zombie z2) {
if (z1.x() > z2.x())
return 1;
if (z1.x() < z2.x())
return -1;
return 0;
}
});
Essentially, a Comparator is a key that signifies how a list should be ordered via its compare method. With the Comparator above, we consider z1 to be greater than z2 if z1 has the higher x value (and we show this by returning 1). Based on this, we sort list.
return; you could do it either way.using JAVA 8 do this:
zombie.sort((Zombie z1, Zombie z2) -> {
if (z1.x() > z2.x())
return 1;
if (z1.x() < z2.x())
return -1;
return 0;
});
List interface now supports the sort method directly
This is old but I found it to be usefull.
zombie.sort((Zombie z1,Zombie z2) -> (Integer.compare(z1.x(),z2.x())));
works too.
List<Zombie> sorted = zombie.stream()
.sorted(Comparator.comparing(Zombie::getX))
.collect(Collectors.toList());
If x is of type int, the idiomatic way is to use Comparator.comparingInt.
List<Zombie> sorted = zombie.stream()
.sorted(Comparator.comparingInt(Zombie::getX))
.collect(Collectors.toList());
zombie itself:zombie.sort(Comparator.comparing(Zombie::getX));
If x is of type int, the idiomatic way is to use Comparator.comparingInt.
zombie.sort(Comparator.comparingInt(Zombie::getX));
