finding closest value in an array

Question

int[] array = new int[5]{5,7,8,15,20};

int TargetNumber = 13;

For a target number, I want to find the closest number in an array. For example, whe

Answer 1

Both Jon and Rich gave great answers with MinBy and ClosestTo. But I would never recommend using OrderBy if your intent is to find a single element. It's far too inefficient for those kinds of tasks. It's simply the wrong tool for the job.

Here's a technique that performs marginally better than MinBy, is already included in the .NET framework, but less elegant than MinBy: Aggregate

var nearest = array.Aggregate((current, next) => Math.Abs((long)current - targetNumber) < Math.Abs((long)next - targetNumber) ? current : next);

As I said, not as elegant as Jon's method, but viable.

Performance on my computer:

1. For(each) Loops = fastest
2. Aggregate = 2.5x slower than loops
3. MinBy = 3.5x slower than loops
4. OrderBy = 12x slower than loops