scala_tutorial

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Scala val pattern = new Regex("abl[ae]\\d+") val str = "ablaw is able1 and cool" println((pattern findAllIn str).mkString(",")) } } Save the above program in Demo.scala. The following commands are used to compile and execute this program. \>scalac Demo.scala \>scala Demo Output: able1 160
19. SCALA – EXCEPTION HANDLING Scala Scala's exceptions work like exceptions in many other languages like Java. Instead of returning a value in the normal way, a method can terminate by throwing an exception. However, Scala doesn't actually have checked exceptions. When you want to handle exceptions, you use a try{...}catch{...} block like you would in Java except that the catch block uses matching to identify and handle the exceptions. Throwing Exceptions Throwing an exception looks the same as in Java. You create an exception object and then you throw it with the throw keyword as follows. throw new IllegalArgumentException Catching Exceptions Scala allows you to try/catch any exception in a single block and then perform pattern matching against it using case blocks. Try the following example program to handle exception. import java.io.FileReader import java.io.FileNotFoundException import java.io.IOException object Demo { def main(args: Array[String]) { try { val f = new FileReader("input.txt") } catch { case ex: FileNotFoundException =>{ println("Missing file exception") } case ex: IOException => { println("IO Exception") 161
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Scala About the Tutorial Scala is a
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Scala 4. SCALA - DATA .............
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Scala Higher-Order Functions ......
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Scala Regular-Expression Examples .
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Scala Scala can Execute Java Code S
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Scala We assume that the readers of
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Scala Windows \>scala -version Scal
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Scala Welcome to Scala version 2.9.
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Scala $salary, 123abc, -salary Oper
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Scala Newline Characters Scala is a
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4. SCALA - DATA Scala Scala has all
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Scala "Hello,\nWorld!" "This string
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5. SCALA - VARIABLES Scala Variable
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Scala } Save the above program in D
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Methods Variables 6. SCALA - CLASSE
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Scala \>scala Demo Output Point x l
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Scala Implicit classes may not be
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7. SCALA - ACCESS MODIFIERS Scala T
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Scala } Scope of Protection Access
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8. SCALA - OPERATORS Scala An opera
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Scala == (Equal) 1 Checks if the va
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Scala It is called Logical AND oper
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Scala Ex: (A & B) will give 12, whi
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Scala \>scala Demo Output: a & b =
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Scala Try the following example pro
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Scala c &= a = 0 c ^= a = 10 c |= a
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9. SCALA - IF ELSE STATEMENT Scala
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Scala if(Boolean_expression){ //Exe
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Scala }else if( x == 30 ){ println(
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10. SCALA - LOOP STATEMENTS Scala T
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Scala while(condition) { Conditiona
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Scala jumps back up to do, and the
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Scala object Demo { } def main(args
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Scala } } Save the above program in
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Scala Scala's for loop allows to fi
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Scala \>scalac Demo.scala \>scala D
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Scala object Demo { def main(args:
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Scala Output: Value of a: 1 Value o
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11. SCALA - FUNCTIONS Scala A funct
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Scala var sum:Int = 0 sum = a + b r
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Scala println("Arg value[" + i + "]
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Scala logWithDateBound("message3" )
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Scala \>scala Demo Output Factorial
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Scala Currying Functions Currying t
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12. SCALA - CLOSURES Scala A closur
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13. SCALA - STRINGS Scala This chap
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Scala "My name is ".concat("Zara");
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Scala val name = “James” printl
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Scala b String Methods Following is
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Scala 27 28 29 30 31 32 33 34 35 36
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14. SCALA - ARRAYS Scala Scala prov
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Scala } println("Total is " + total
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Scala Save the above program in Dem
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Scala print( " " + x ) } println()
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15. SCALA - COLLECTIONS Scala Scala
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Scala val nums = Nil println( "Head
Page 118 and 119: Scala } Save the above program in D
Page 120 and 121: Scala 1 2 3 4 5 6 7 8 9 10 11 12 13
Page 122 and 123: Scala 34 35 36 37 38 39 40 41 42 43
Page 126 and 127: Scala Find Common Values Insets You
Page 128 and 129: Scala 14 def diff(that: Set[A]): Se
Page 130 and 131: Scala 39 def sum: A Returns the sum
Page 132 and 133: Scala val nums: Map[Int, Int] = Map
Page 134 and 135: Scala colors.keys.foreach{ i => pri
Page 136 and 137: Scala 5 def iterator: Iterator[(A,
Page 138 and 139: Scala 30 def min: (A, B) Finds the
Page 140 and 141: Scala You can use Tuple to write a
Page 142 and 143: Scala Concatenated String: (1,hello
Page 144 and 145: Scala } } Save the above program in
Page 146 and 147: Scala 2 def isEmpty: Boolean Return
Page 148 and 149: Scala number of words Find Min & Ma
Page 150 and 151: Scala 4 def ++[B >: A](that :=> Gen
Page 152 and 153: Scala 28 def max: A Finds the large
Page 154 and 155: 16. SCALA - TRAITS Scala A trait en
Page 156 and 157: Scala Value classes and Universal T
Page 158 and 159: 17. SCALA - PATTERN MATCHING Scala
Page 160 and 161: Scala val charlie = new Person("Cha
Page 162 and 163: 18. SCALA - REGULAR EXPRESSIONNS Sc
Page 166 and 167: Scala \\n Back-reference to capture
Page 170 and 171: Scala } } } } Save the above progra
Page 172 and 173: 20. SCALA - EXTRACTORS Scala An ext
Page 174 and 175: Scala def main(args: Array[String])
Page 176 and 177: Scala print("Please enter your inpu
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