How to know if a List is homogeneous

Question

I want to know if a List is homogeneous.

Here is my code :

def isHomogeneous(ls: List[Any]) = ls.map(_.getClass).toSet.size == 1

Is there a better way ?

Answer 1

def allEqual(xs: Traversable[_]) =
  xs.headOption.forall(head => xs.forall(_ == head))

def isHomogeneous(xs: Traversable[_]) =
  allEqual(xs.view.map(_.getClass))

• Keeps the getClass business separate from the traversal.
• Uses more general type Traversable instead of List.
• Works for Nil.
• Does not traverse the entire collection unless necessary.