2019-03-05 · A powerful Scala idiom is to use the Option class when returning a value from a function that can be null. Simply stated, instead of returning one object when a function succeeds and null when it fails, your function should instead return an instance of an Option , where the instance is either:

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An Option[T] can be either Some[T] or None object, which represents a missing value. For instance, the get method of Scala's Map produces Some(value) if a value corresponding to a given key has been found, or None if the given key is not defined in the Map.. Option type is used frequently in Scala programs and you can 2021-02-05 2019-03-05 Option comes to the rescue. Our problem is that we need to find a way to say that something has two states, it either has a value or it doesn’t. This idea is prevalent in functional programming in general and the solution is the Option (ML, Scala) or Maybe (Haskell) type.

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Using Option/Some/None. Scala’s solution to this problem is to use a trio of classes known as Option, Some, and None. The Some and None classes are subclasses of Option, so the solution works like this: You declare that toInt returns an Option type; If toInt receives a string it can convert to an Int, you wrap the Int inside of a Some Scala options: Option contains two values none and some other value. In Scala, options are used when a function may or may not return a value. In this Scala tutorial on options, we will learn how to initialize, and perform functions on options with working examples.

Consider an example of how to create a option; val msg : Option [ String] = Some ("Option is a Scala collection") Scala program that uses Option with Map val ids = Map (("a12", "Mark"), ("b19", "Michelle")) // Get Option from our map. val result = ids.get ("b19") if (result.

It is another option for you who want to design your home interior with a cool style. The cost for making a concrete staircase can be calculated by focusing on the 

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The Option in Scala is referred to a carrier of single or no element for a stated type. When a method returns a value which can even be null then Option is utilized i.e, the method defined returns an instance of an Option, in place of returning a single object or a null.

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By using Scala options, you are forced to explicitly address null or empty values at the type level. Scala Option Basic Example: Granted, you can write Scala code much like you would Java, with vars and loops and leaning on imperative O-O patterns, but the language really sings if you can wrap your head around FP, and I would claim that the use of things like Option is heavily rooted in FP. scala> val optInt: Option[Int] = None optInt: Option[Int] = None scala> val optString: Option[String] = None optString: Option[String] = None The terms None, Nothing and null can get confusing here; let’s recap what each of them means. None is an instance of the class Option, and it represents a missing nullable value.
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