Find the nearest/closest value in a sorted List

Question

I was wondering if it is possible to find the closest element in a List for a element that is not there.

For example if we had the valu

Answer 1

It seems like the easiest way is simply to iterate over the sorted list, checking each item.

List<Integer> ints = new ArrayList<>();
ints.add(1);
ints.add(3);
ints.add(6);
ints.add(7);

Collections.sort(ints);

int target = 4;
int nearest = 0;

for (int i : ints)
{
    if (i <= target) {
        nearest = i;
    }
}

System.out.println(nearest);

This outputs the largest item in the list which is less than or equal to the target.

Answer 2

You need Array.binarySearch, docs.

Returns: index of the search key, if it is contained in the array; otherwise, (-(insertion point) - 1). The insertion point is defined as the point at which the key would be inserted into the array: the index of the first element greater than the key, or a.length if all elements in the array are less than the specified key.