title: Kotlin - Filter/Map from two Collections
body: <p>Is it possible to filter and map two Collections based on desired criteria match like the following:</p>
  
  <pre><code>fun main(args: Array&lt;String&gt;) {
      val selectedDates = listOf("2018-08-12", "2018-08-13", "2018-08-14")
  
      val expenses = listOf(Expense("Food", "2018-08-12"),
      Expense("Transportation", "2018-08-15"),
      Expense("Misc.", "2018-08-13"),
       Expense("Uber", "2018-08-12"),
      Expense("Clothing", "2018-08-16"))
  
      val listOfExpensesInSelectedDate = mutableListOf&lt;Expense&gt;()
  
      for (date in selectedDates){
          listOfExpensesInSelectedDate.addAll(expenses.filter { it.date==date })
  
      }
      println(listOfExpensesInSelectedDate)
  
  }
  
  data class Expense(
          val expense:String,
          val date: String
  )
  </code></pre>
  
  <p>Provided the given code above, I am trying to return a list of Expenses that match with the dates from another list of Strings.  In the example above, I have used both for Loop and filter function to get my desired result.  But is it possible to avoid the for loop and filter and map both the Collections in single line of code?</p>