Assign an underscore to a variable. What does underline do?

Question

I recently came across the following code:

var myVariable: variableKind = _

This seems to be a way to appropriate null myVariable.

Can someone explain the rationale _in this case? What is the difference between assigning a variable _and a nullvariable?

Answer 1

It initializes the variable with a default value - this value depends on the type. For numeric types, this is zero, falsefor booleans, ()for Unitand null for types that extend AnyRef.

Answer 2

. "variableKind" AnyRef, ( ) null. ..