Question

For example suppose I have the following

  var lastSecurity = ""

  def allSecurities = for {
    security <- lastTrade.keySet.toList
    lastSecurity = security
  } yield security

At the moment

lastSecurity = security

Seems to be creating a new variable in scope rather than modifying the variable declared in the first line of code.

Answer 1

Try this:

var lastSecurity = ""

def allSecurities = for {
  security <- lastTrade.keySet.toList
} yield {
  lastSecurity = security
  security
}