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} } When the above code is compiled and executed, it produces the following result: C:/>scalac Test.scala C:/>scala Test a.getOrElse(0): 5 b.getOrElse(10): 10 C:/> Using isEmpty() Method: Following is the example of showing how to use isEmpty() to check if the option is None or not: object Test { def main(args: Array[String]) { val a:Option[Int] = Some(5) val b:Option[Int] = None } } println("a.isEmpty: " + a.isEmpty ) println("b.isEmpty: " + b.isEmpty ) When the above code is compiled and executed, it produces the following result: C:/>scalac Test.scala C:/>scala Test a.isEmpty: false b.isEmpty: true C:/> Scala Option Methods: Following are the important methods which you can use while playing with Options. For a complete list of methods available, please check official documentation of Scala. SN Methods with Description 1 2 3 4 5 def get: A Returns the option's value. def isEmpty: Boolean Returns true if the option is None, false otherwise. def productArity: Int The size of this product. For a product A(x_1, ..., x_k), returns k def productElement(n: Int): Any The nth element of this product, 0-based. In other words, for a product A(x_1, ..., x_k), returns x_(n+1) where 0 < n < k. def exists(p: (A) => Boolean): Boolean Returns true if this option is nonempty and the predicate p returns true when applied to this Option's value. Otherwise, returns false. TUTORIALS POINT Simply Easy Learning
6 7 8 9 10 11 12 13 14 def filter(p: (A) => Boolean): Option[A] Returns this Option if it is nonempty and applying the predicate p to this Option's value returns true. Otherwise, return None. def filterNot(p: (A) => Boolean): Option[A] Returns this Option if it is nonempty and applying the predicate p to this Option's value returns false. Otherwise, return None. def flatMap[B](f: (A) => Option[B]): Option[B] Returns the result of applying f to this Option's value if this Option is nonempty. Returns None if this Option is empty. def foreach[U](f: (A) => U): Unit Apply the given procedure f to the option's value, if it is nonempty. Otherwise, do nothing. def getOrElse[B >: A](default: => B): B Returns the option's value if the option is nonempty, otherwise return the result of evaluating default. def isDefined: Boolean Returns true if the option is an instance of Some, false otherwise. def iterator: Iterator[A] Returns a singleton iterator returning the Option's value if it is nonempty, or an empty iterator if the option is empty. def map[B](f: (A) => B): Option[B] Returns a Some containing the result of applying f to this Option's value if this Option is nonempty. Otherwise return None. def orElse[B >: A](alternative: => Option[B]): Option[B] Returns this Option if it is nonempty, otherwise return the result of evaluating alternative. 15 def orNull Returns the option's value if it is nonempty, or null if it is empty. Scala Iterators An iterator is not a collection, but rather a way to access the elements of a collection one by one. The two basic operations on an iterator it are next and hasNext. A call to it.next() will return the next element of the iterator and advance the state of the iterator. You can find out whether there are more elements to return using Iterator's it.hasNext method. The most straightforward way to "step through" all the elements returned by an iterator is to use a while loop. Let us see a real example: object Test { def main(args: Array[String]) { val it = Iterator("a", "number", "of", "words") } } while (it.hasNext){ println(it.next()) } When the above code is compiled and executed, it produces the following result: C:/>scalac Test.scala C:/>scala Test a number TUTORIALS POINT Simply Easy Learning
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Scala Tutorial
Page 3 and 4:
ABOUT THE TUTORIAL Scala Tutorial S
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FLOATING POINT LITERALS ...........
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Scala Strings .....................
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CHAPTER 1 Scala Overview Scala, sho
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CHAPTER 2 Scala Environment Setup T
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$scala -version Scala code runner v
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} * This will print 'Hello World' a
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forSome If implicit import Lazy Mat
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CHAPTER 4 Scala Data Types Scala ha
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Characters must not necessarily be
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Variable Type Inference: When you a
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The access to f in class Sub is OK
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var a = 10; var b = 20; var c = 25;
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} } println("a && b = " + (a&&b) );
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a >>> 15 C:/> Assignment Operators:
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Here, operators with the highest pr
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} If the boolean expression evaluat
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Nested if...else Statement: It is a
Page 39 and 40: while loop do...while loop for loop
Page 41 and 42: Flow Diagram: Example: object Test
Page 43 and 44: When the above code is compiled and
Page 45 and 46: } } // for loop execution with mult
Page 47 and 48: Flow Diagram: Example: import scala
Page 49 and 50: Infinite Loop: A loop becomes infin
Page 51 and 52: } } return sum A function, which do
Page 53 and 54: When the above code is compiled and
Page 55 and 56: } When the above code is compiled a
Page 57 and 58: } logWithDateBound("message1" ) log
Page 59 and 60: CHAPTER 12 Scala Strings Consider t
Page 61 and 62: } } var str2 = "Tod"; println("Dot
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Page 65 and 66: CHAPTER 13 Scala Arrays Scala provi
Page 67 and 68: C:/> Multi-Dimensional Arrays: Ther
Page 69 and 70: C:/> Scala Arrays Methods: Followin
Page 71 and 72: Scala Lists Scala Lists are quite s
Page 73 and 74: Creating Uniform Lists: You can use
Page 75 and 76: 13 14 15 16 17 18 19 20 21 22 23 24
Page 77 and 78: var s = Set(1,3,5,7) While defining
Page 79 and 80: C:/> Scala Set Methods: Following a
Page 81 and 82: elements. 38 39 40 41 42 43 44 45 4
Page 83 and 84: use two maps with ++ as method colo
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Page 87 and 88: val t = new Tuple3(1, "hello", Cons
Page 89: The method will return Some[Person]
Page 93 and 94: Scala Iterator Methods: Following a
Page 95 and 96: 38 39 40 41 42 43 44 45 46 47 48 49
Page 97 and 98: CHAPTER 15 Scala Classes & Objects
Page 99 and 100: } } println ("Point y location : "
Page 101 and 102: CHAPTER 16 Scala Traits A trait enc
Page 103 and 104: CHAPTER 17 Scala Pattern Matching P
Page 105 and 106: } // case class, empty one. case cl
Page 107 and 108: } When the above code is compiled a
Page 109 and 110: [0-9] Match any digit; same as [012
Page 111 and 112: CHAPTER 19 Scala Exception Handling
Page 113 and 114: CHAPTER 20 Scala Extractors An extr
Page 115 and 116: CHAPTER 21 Scala Files I/O Scala is
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