Find Min and Max of a Collection in Scala

1. Overview

In this tutorial, we’ll see how to find the min and max of different collections in Scala.

2. Find the Min and Max of a Collection

Scala provides several generic methods for all collections. Fortunately for us, it offers easy-to-use methods to find the min and max of collections.

In this section, we’ll see examples using List, Set, Array, Vector, and Seq.

2.1. List

Let’s use List as our first example to find the min and max:

scala> val lst = List(3,4,1,2)
lst: List[Int] = List(3, 4, 1, 2)
scala> lst.min
res0: Int = 1

scala> lst.max
res1: Int = 4

As we can see, it’s very simple to get the min and max elements of a List.

But what happens if the List is empty? Let’s take a look:

scala> val empty = List.empty[Int]
empty: List[Int] = List()

scala> empty.max
java.lang.UnsupportedOperationException: empty.max
  at scala.collection.TraversableOnce.max(TraversableOnce.scala:275)
  at scala.collection.TraversableOnce.max$(TraversableOnce.scala:273)
  at scala.collection.AbstractTraversable.max(Traversable.scala:108)
  ... 26 elided

We get an exception if we try to find the max or min of an empty List. The same thing will also happen for every other collection mentioned in this article.

2.2. Set

Here’s how we find the min and max of a Set:

scala> val s = Set(1,2,3,4)
s: scala.collection.immutable.Set[Int] = Set(1, 2, 3, 4)

scala> s.max
res0: Int = 4

scala> s.min
res1: Int = 1

2.3. Array

Let’s see how we can  find the min and max of an Array:

scala> val arr = Array(1,4,3,2)
arr: Array[Int] = Array(1, 4, 3, 2)

scala> arr.max
res2: Int = 4

scala> arr.min
res3: Int = 1

2.4. Vector

Now, let’s find the min and max of a Vector:

scala> val vec = Vector(1,4,3,2)
vec: scala.collection.immutable.Vector[Int] = Vector(1, 4, 3, 2)

scala> vec.max
res4: Int = 4

scala> vec.min
res5: Int = 1

2.5. Seq

Finally, let’s find the min and max of an Seq:

scala> val seq = Seq(1,4,3,2)
seq: Seq[Int] = List(1, 4, 3, 2)

scala> seq.max
res6: Int = 4

scala> seq.min
res7: Int = 1

As we can see, the usage is the same, and the result is the expected one.

3. Conclusion

In this article, we saw how to find the min and max of different collections in Scala.