scala-tuples-maps

FAQ

Q. What is the difference between arrays ans tuples?
A. Tuples are just like arrays but they are immutable.

Q. Can we traverse a tuple using foreach loop?
A. Yes we can, but we have to use the tuple function .productIterator for doing the same.

Q. What datatypes are allowed for keys or values in a map?
A. No limitations whatsoever, you can store any datatype for keys as well as values.

Q. Can we edit or add new values to a map?
A. No by default maps are immutable, for such operations you have to create a mutable map.

MCQ

Q. For a tuple ("hi", "hello", "hola", "namaste"), what will be the output of this line of code?
   println(s"$tup._2 ; $tup(3)")
a. hola ; namaste
b. hello ; hola
c. hola ; hola
d. hello ; namaste

A. d. hello ; namaste

Q. What will be the output for this snippet?
   val map = Map(1 -> 1, 2 -> 2, 3 -> 3)
   map("1") = "5"
   println(map)
a. HashMap(1 -> 1, 1 -> 5, 2 -> 2, 3 -> 3)
b. HashMap(1 -> 5, 2 -> 2, 3 -> 3)
c. HashMap(1 -> 1, 2 -> 2, 3 -> 3, 1 -> 5)
d. None of these

A. d. None of these

Q. Which is the correct code to create a mutable map?
a. val map = Map("PEP" -> "CODING", 10 -> "TEN", "two" -> 2)
b. val map = collection.MutableMap("PEP" -> "CODING", 10 -> "TEN", "two" -> 2)
c. val map = collection.Map.mutable("PEP" -> "CODING", 10 -> "TEN", "two" -> 2)
d. val map = collection.mutable.Map("PEP" -> "CODING", 10 -> "TEN", "two" -> 2)

A. d. val map = collection.mutable.Map("PEP" -> "CODING", 10 -> "TEN", "two" -> 2)

Q. Which statement is able to print the values of a tuple "tup"?
a. tup.productIterator.foreach{i => print(s"$i" + ", ")}
b. tup.foreach.productIterator{i => print(s"$i" + ", ")}
c. productIterator.tup.foreach{i => print(s"$i" + ", ")}
d. None of these

A. a. tup.productIterator.foreach{i => print(s"$i" + ", ")}