Scala placeholder syntax

Question

There is something that I can\'t quite understand hope someone can shed some light.. I have Seq[String]

val strDeps: Seq[String] = ...

and

Answer 1

_ expands only to the smallest possible scope.

The inner _.reverse part is already interpreted as x => x.reverse therefore the parameter is missing inside sortWith.

Answer 2

compareTo(_)

Is a partially applied method. It just means "compareTo, but without applying the first parameter". Note that _ is not a parameter. Rather, it indicates the absence of a parameter.

compareTo(_.reverse)

Is a method taking an anonymous function as parameter, the parameter being _.reverse. That translates to x => x.reverse.