{"id":13965,"date":"2018-05-29T06:01:03","date_gmt":"2018-05-29T06:01:03","guid":{"rendered":"https:\/\/data-flair.training\/blogs\/?p=13965"},"modified":"2021-12-04T10:15:41","modified_gmt":"2021-12-04T04:45:41","slug":"scala-option","status":"publish","type":"post","link":"https:\/\/data-flair.training\/blogs\/scala-option\/","title":{"rendered":"Scala Option – 13 Simple Methods to Call Option in Scala"},"content":{"rendered":"

In this Scala tutorial<\/strong><\/a>, we are going to learn about what is Scala Option. Moreover, we will see Scala Option getOrElse() Method, and Scala isEmpty() Method. Along with this we will discuss several Methods to Call on an Option in Scala:\u00a0def get: A,\u00a0def isEmpty: Boolean, def productArity: Int,\u00a0def productElement(n: Int): Any, def exists(p: (A) => Boolean): Boolean,\u00a0def orNull etc.<\/p>\n

So, let’s explore Scala Option.<\/p>\n

\"Scala<\/a>

Scala Option – 13 Simple Methods to Call Option in Scala<\/p><\/div>\n

Scala Option<\/h3>\n

A Scala Option holds zero or one element of a type. This means that it is either a Some[T] or a none object. One place we get an Option value is through the get() method for a Map.<\/p>\n

Let’s Learn Scala Map with Examples Quickly & Effectively<\/a><\/strong><\/p>\n

We have a Map m here:<\/p>\n

scala> m\r\nres109: scala.collection.immutable.Map[String,Int] = Map(Ayushi -> 0, Megha -> 1, Ruchi -> 2)\r\nscala> m.get(\"Megha\")\r\nres110: Option[Int] = Some(1)\r\nscala> m.get(\"Fluffy\")\r\nres111: Option[Int] = None<\/pre>\n
Here, it returns Some(1) when it finds the key \u201cMegha\u201d in the Map (where 1 is the value for that key). And when it doesn\u2019t find the key \u201cFluffy\u201d in there, it returns None, stating that it couldn\u2019t find the key. This is like java.util.HashMap in Java<\/a><\/strong>.<\/p>\n
We can also implement a pattern match here.<\/p>\n
scala> def show(x:Option[Int])=x match{\r\n    | case Some(i)=>i\r\n    | case None=>\"?\"\r\n    | }\r\nshow: (x: Option[Int])Any\r\nscala> show(m.get(\"Ayushi\"))\r\nres113: Any = 0\r\nscala> show(m.get(\"Fluffy\"))\r\nres114: Any = ?<\/pre>\n
Learn: Scala Closures with Examples | See What is Behind the Magic<\/a><\/strong><\/p>\n
getOrElse() Method<\/h3>\n
This is like get(), except it will give us the default when no value exists. Let\u2019s take two values \u2018a\u2019 and \u2018b\u2019.<\/p>\n
scala> val a:Option[Int]=Some(5)\r\na: Option[Int] = Some(5)\r\nscala> val b:Option[Int]=None\r\nb: Option[Int] = None\r\nAnd now, the paydirt.\r\nscala> a.getOrElse(1)\r\nres0: Int = 5<\/pre>\n
This checks if \u2018a\u2019 has a value. Since it does, this returns that value, which is 5.<\/p>\n
scala> b.getOrElse(7)\r\nres1: Int = 7<\/pre>\n
Now here, since \u2018b\u2019 has no value, this returns the default, which is 7, as we state.<\/p>\n
Scala isEmpty() Method<\/h3>\n
If the Scala Option is None, this returns true; otherwise, it returns false.<\/p>\n
scala> a.isEmpty\r\nres2: Boolean = false\r\nscala> b.isEmpty\r\nres3: Boolean = true<\/pre>\n
Learn: Scala Arrays and Multidimensional Arrays in Scala<\/a><\/strong><\/p>\n
Methods to Call on an Option in Scala<\/h3>\n
These are some of the methods you will commonly use to call Scala Option.<\/p>\n
a. def get: A<\/h4>\n
This will return the Option\u2019s value.<\/p>\n
scala> a.get\r\nres5: Int = 5\r\nscala> b.get\r\njava.util.NoSuchElementException: None.get\r\n at scala.None$.get(Option.scala:349)\r\n at scala.None$.get(Option.scala:347)\r\n ... 28 elided<\/pre>\n
b. def isEmpty: Boolean<\/h4>\n
If the Scala Option is None, this returns true. Otherwise, it returns true.<\/p>\n
scala> a.isEmpty\r\nres7: Boolean = false\r\nscala> b.isEmpty\r\nres8: Boolean = true<\/pre>\n
c. def productArity: Int<\/h4>\n
This Scala Option returns the size of the product.<\/p>\n
scala> a.productArity\r\nres9: Int = 1\r\nscala> b.productArity\r\nres10: Int = 0<\/pre>\n
A product A(x_1, …, x_k) has size k
\nRead Scala String: Creating String, Concatenation, String Length in detail<\/a><\/strong><\/p>\n
d. def productElement(n: Int): Any<\/h4>\n
This returns the n-th element of product, where indexing begins at 0.<\/p>\n
scala> a.productElement(0)\r\nres11: Any = 5\r\nscala> a.productElement(1)\r\njava.lang.IndexOutOfBoundsException: 1\r\n at scala.Some.productElement(Option.scala:333)\r\n ... 28 elided\r\nscala> b.productElement(0)\r\njava.lang.IndexOutOfBoundsException: 0\r\n at scala.None$.productElement(Option.scala:347)\r\n ... 28 elided<\/pre>\n
e. def exists(p: (A) => Boolean): Boolean<\/h4>\n
If the Scala Option has a value, and this value satisfies the predicate, this returns true. Otherwise, this returns false.<\/p>\n
scala> a.exists(x=>{x%2!=0})\r\nres14: Boolean = true<\/pre>\n
f. def filter(p: (A) => Boolean): Option[A]<\/h4>\n
If the Scala Option\u2019s value satisfies the predicate, this returns that value.<\/p>\n
scala> a.filter(x=>{x%2!=0})\r\nres15: Option[Int] = Some(5)<\/pre>\n
g. def filterNot(p: (A) => Boolean): Option[A]<\/h4>\n
If the Option\u2019s value does not satisfy the predicate, this returns that value.<\/p>\n
scala> a.filterNot(x=>{x%2!=0})\r\nres16: Option[Int] = None\r\nscala> a.filterNot(x=>{x%2==0})\r\nres17: Option[Int] = Some(5)<\/pre>\n
h. def flatMap[B](f: (A) => Option[B]): Option[B]<\/h4>\n
If the Option has a value, this applies the function to that value, and then returns it.<\/p>\n
Do you know about Scala Arrays and Multidimensional Arrays<\/a><\/strong><\/p>\n
i. def foreach[U](f: (A) => U): Unit<\/h4>\n
It applies the procedure to the Option\u2019s value and returns it. If the Scala Option is None, this does nothing.<\/p>\n
j. def getOrElse[B<\/strong> >: A](default: => B): B<\/h4>\n
If the Option has a value, this returns it; otherwise, returns the default value.<\/p>\n
scala> a.getOrElse(7)\r\nres3: Int = 5\r\nscala> b.getOrElse(7)\r\nres4: Int = 7<\/pre>\n
Learn: Scala Operator<\/a><\/strong><\/p>\n
k. def isDefined: Boolean<\/h4>\n
If the Option is an instance of Some, this returns true; otherwise, false.<\/p>\n
scala> a.isDefined\r\nres5: Boolean = true\r\nscala> b.isDefined\r\nres6: Boolean = false<\/pre>\n
l. def iterator: Iterator[A]<\/h4>\n
This returns an iterator on the Option.<\/p>\n
scala> a.iterator\r\nres8: Iterator[Int] = non-empty iterator\r\nscala> for(i<-a.iterator){println(i)}<\/pre>\n
5<\/p>\n
m. def map[B](f: (A) => B): Option[B]<\/h4>\n
If the Option has a value, it applies this function to it, and then returns it.<\/p>\n
scala> a.map(x=>{x*x})\r\nres10: Option[Int] = Some(25)<\/pre>\n
n. def orElse[B >: A](alternative: => Option[B]): Option[B]<\/h4>\n
If the Option has a value, this returns that. Otherwise, this evaluates the alternative and returns it.
\nMust Read about Scala Iterator in Detail<\/a><\/strong><\/p>\n
o. def orNull<\/h4>\n
If the Option has a value, this returns it. Otherwise, this returns Null.<\/p>\n
So, this was all on Scala Option. Hope you like our explanation.<\/p>\n
Conclusion<\/h3>\n
Hence, we studied Scala Option. In addition, we discussed Scala Option getOrElse() Method and Scala isEmpty() Method. At last, we saw several Methods to Call on an Option in Scala. Furthermore, if you have any query, feel free to ask in the comment box.<\/p>\n
Related Topics-\u00a0Scala Closures with Examples\u00a0<\/a><\/strong><\/p>\n
For reference<\/a><\/strong>
In this Scala tutorial, we are going to learn about what is Scala Option. Moreover, we will see Scala Option getOrElse() Method, and Scala isEmpty() Method. Along with this we will discuss several Methods...<\/p>\n","protected":false},"author":6,"featured_media":16847,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[61],"tags":[3689,3692,3693,3694,3695,3697,3698,7320,8696,12483,12517],"class_list":["post-13965","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-scala","tag-def-foreachuf-a-u-unit","tag-def-isdefined-boolean","tag-def-isempty-boolean","tag-def-iterator-iteratora","tag-def-mapbf-a-b-optionb","tag-def-ornull","tag-def-productarity-int","tag-isempty-method","tag-methods-to-call-on-an-option","tag-scala-isempty-method","tag-scala-option"],"yoast_head":"\nScala Option - 13 Simple Methods to Call Option in Scala - DataFlair<\/title>\n<meta name=\"description\" content=\"Scala Option- Scala Option getOrElse() Method, Scala isEmpty() Method, Methods to Call on an Option in Scala, def isEmpty: Boolean, def productArity: Int\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/data-flair.training\/blogs\/scala-option\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Scala Option - 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