Scala Trait Traversable | Set-2

Last Updated : 24 Jan, 2022

prerequisite- Scala Trait Traversable | Set-1
In the previous Set we have seen some of the operations performed by the Class Taversable. Now, in this Set we will perceive some more operations.
These operations are as follows:

Conversion operations:
The Conversion operations are toList, toSeq, toArray, toStream, toSet, toMap, toIterable, and toIndexedSeq. These operations changes the Collection of Traversable into a relatively distinct thing.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating Set of numbers          val q = Set(2, 7, 8, 15, 19)          // Converting Set to an Array         val r = q.toArray           // Displaying an Array         println(r)     } }

Output:

[I@506e1b77

Here, the Conversion operation i.e, toArray will convert the above Set (or any Traversable) into an Array.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating Set of numbers          val q = Set(2, 6, 3, 7, 15, 20)          // Converting a Set to a List         val r = q.toList          // Displaying a List         println(r)              } }

Output:

List(20, 6, 2, 7, 3, 15)

Here, toList will convert any Collection of Traversable into a List.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating List of numbers          val x = List(9, 10, 13, 15, 18, 19)          // Converting a List to a Set         val y = x.toSet          // Displaying a Set         println(y)     } }

Output:

Set(10, 9, 13, 18, 19, 15)

Here, the Conversion operation i.e, toSet will convert any collection of Traversable into a Set.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating Set of numbers          val m = Set(2, 4, 6, 8, 11, 15)          // Converting a Set to a Sequence         val n = m.toSeq          // Displaying a Sequence         println(n)     } }

Output:

ArrayBuffer(6, 2, 11, 8, 4, 15)

Here, Conversion operation i.e, toSeq converts any Collection of Traversable into a Sequence. The sequence generated here is utilized in Vectors.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating Set of numbers          val x = Set(8, 10, 13, 15, 18)          // Converting a Set to an Iterable         val y = x.toIterable          // Displaying an iterable         println(y)     } }

Output:

Set(10, 13, 18, 8, 15)

Here, the Conversion operation i.e, toIterable (It Iterates over all the elements of the collection) will convert any collection of a Traversable into an Iterable.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating Set of numbers          val x = Set(2, 4, 5, 6, 7, 9)          // Converting a Set to an          // Indexed sequence          val y = x.toIndexedSeq          // Displaying an Indexed sequence         println(y)     } }

Output:

Vector(5, 6, 9, 2, 7, 4)

Here, the conversion operation i.e, toIndexedSeq converts any Traversable into an Indexed sequence. The Indexed sequence generated here is utilized in Strings and Vectors.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating Set of numbers          val x = Set(15, 17, 18, 19, 22, 25)          // Converting a Set to a stream          val y = x.toStream          // Displaying a Stream         println(y)     } }

Output:

Stream(25, ?)

Here, the Conversion operation i.e, toStream converts any collection of Traversable into a Stream. This Stream is enumerated lazily.
Example :

Scala

// Scala program of Conversion operation  // Creating object  object Conversion {      // Main method     def main(args: Array[String])      {          // Creating a Set of parameters          val x = Set(&quot;GfG&quot; -&gt; &quot;CS portal&quot;, &quot;Nidhi&quot; -&gt; &quot;a Geek&quot;)          // Converting a Set to a Map         val y = x.toMap          // Displaying a Map         println(y)     } }

Output:

Map(GfG -> CS portal, Nidhi -> a Geek)

Here, toMap will convert any Traversable to a Map. A Set or a List must have parameters.
Size info operations:
The Size info operations are nonEmpty, isEmpty, hasDefiniteSize, and size. These operations can specify if the given operation is finite or infinite.
Example :

Scala

// Scala program of Size info operation  // Creating object  object Sizeinfo {      // Main method     def main(args: Array[String])      {          // Creating a map          val x = Map(&quot;gfg&quot; -&gt; &quot;cs&quot;, &quot;nidhi&quot; -&gt; &quot;geek&quot;)          // Applying Size info operation         val y = x.isEmpty          // Displays true if map is          // empty         println(y)     } }

Output:

false

Here, isEmpty checks if the Traversable collection is empty. If the collection of elements is empty then it prints true and if its not empty then it prints false.
Example :

Scala

// Scala program of Size info operation  // Creating object  object Sizeinfo {      // Main method     def main(args: Array[String])      {          // Creating a map          val x = Map(&quot;gfg&quot; -&gt; &quot;cs&quot;, &quot;nidhi&quot; -&gt; &quot;geek&quot;)          // Applying Size info operation         val y = x.nonEmpty          // Displays true if map is          // not empty         println(y)     } }

Output:

true

Here, nonEmpty checks if the Traversable collection contains elements. If there are elements in the collection then it displays true else false.
Example :

Scala

// Scala program of Size info operation  // Creating object  object Sizeinfo {      // Main method     def main(args: Array[String])      {          // Creating a map          val q = Map(&quot;gfg&quot; -&gt; &quot;cs&quot;, &quot;nidhi&quot; -&gt; &quot;geek&quot;,                                     &quot;geeta&quot; -&gt; &quot;coder&quot;)          // Applying Size info operation         val r = q.size          // Displays size of the Map         println(r)     } }

Output:

Here, size is utilized to evaluate the size of Traversable collection.
Example :

Scala

// Scala program of Size info operation  // Creating object  object Sizeinfo {      // Main method     def main(args: Array[String])      {          // Creating a map          val q = Map(&quot;gfg&quot; -&gt; &quot;cs&quot;, &quot;nidhi&quot; -&gt; &quot;geek&quot;,                                     &quot;geeta&quot; -&gt; &quot;coder&quot;)          // Applying Size info operation         val r = q.hasDefiniteSize          // Displays true if number of         // elements in Map are finite         println(r)     } }

Output:

true

Here, hasDefiniteSize is utilized to check if the Traversable collection has finite elements or not. If the collection is finite then it returns true else false.
Element retrieval operations:
The Element retrieval operations includes last, head, lastOption, headOption, and find. These operations are utilized to retrieve first or last element of the Traversable collection or to retrieve the first element corresponding to the given condition.
Example :

Scala

// Scala program of Element  // retrieval operation  // Creating object  object Retrieval {      // Main method     def main(args: Array[String])      {          // Creating a Set of numbers          val x = Set(12, 13, 14, 15)          // Applying element retrieval          // operation         val y = x.lastOption          // Displays last element         // of the Set         println(y)     } }

Output:

Some(15)

Here, last element of the Traversable is returned by lastOption. The stated collection must be ordered, if there are no elements in the collection then None is returned.
Example :

Scala

// Scala program of Element  // retrieval operation  // Creating object  object Retrieval {      // Main method     def main(args: Array[String])      {          // Creating a Set of numbers          val x = Set(12, 13, 14, 15)          // Applying element retrieval          // operation         val y = x.last          // Displays last element         // of the Set         println(y)     } }

Output:

Here, last will return the last element of the stated collection. The collection must be ordered, if its not ordered then some random element is returned.
Example :

Scala

// Scala program of Element  // retrieval operation  // Creating object  object Retrieval {      // Main method     def main(args: Array[String])      {          // Creating a List of numbers          val q = List(12, 24, 36, 48)          // Applying element retrieval          // operation         val r = q.head          // Displays first element         // of the List         println(r)     } }

Output:

Here, head will return first element of the Traversable collection if its ordered and if the collection is not ordered then any random element is returned.
Example:

Scala

// Scala program of Element  // retrieval operation  // Creating object  object Retrieval {      // Main method     def main(args: Array[String])      {          // Creating a List of numbers          val x = List(8, 10, 21, 17, 29)          // Applying element retrieval          // operation          val y = x.find(_ % 3 == 0)           // Displays first element         // matching the condition         println(y)      } }

Output:

Some(21)

Here, find will retrieve the first element of the collection, which matches the stated condition.
Example :

Scala

// Scala program of Element  // retrieval operation  // Creating object  object Retrieval {      // Main method     def main(args: Array[String])      {              // Creating List of numbers          val p = List(7, 9, 11, 19, 21)          // Creating a empty List          val q = List()          // Applying element retrieval          // operation          val r = p.headOption          val s = q.headOption           // Displays first element         // if the List is not empty         println(r)         println(s)      } }

Output:

Some(7) None

Here, headOption returns first element of an ordered collection but returns None if the collection is empty.

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Scala Trait Traversable | Set-2

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