Sorting objects based on Double values?

Question

Sorting objects is simple enough by mixing in Ordered and providing a compare() function, as shown here. But what if your sorting value is a Double instead of an Int?

def compare(that: MyClass) = this.x - that.x

where x is a Double will lead to a compiler error: "type mismatch; found: Double required: Int"

Is there a way to use Doubles for the comparison instead of casting to Ints?

This idiom is broken also for integer types, as it will produce wrong results on overflow. — starblue, Aug 04 '09 at 19:37

score 8 · Accepted Answer · answered Aug 04 '09 at 19:33

The simplest way is to delegate to compare implementation of RichDouble (to which your Double will be implicitly converted):

def compare(that : MyClass) = x.compare(that.x)

The advantage of this approach is that it works the same way for all primitive types.

Sorting objects based on Double values?

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