hhimanshu · June 15, 2025 03:59 · Sep 24, 2015 · Sep 24, 2015 · Sep 15, 2015 · Sep 15, 2015
diff --git a/Chapter09.scala b/Chapter09.scala
@@ -119,3 +119,4 @@ scala>
 1048576.0	9.5367431640625E-7
 */
 
+// skipping 6-10
diff --git a/Chapter09.scala b/Chapter09.scala
@@ -76,4 +76,46 @@ res11: Double = 15.36
 scala> numbers.sum/numbers.size
 res12: Double = 3.84
 
-
+ /**
+  * 5. Write a Scala program that writes the powers of 2 and their reciprocals to a file, with the exponent ranging from 0 to 20. Line up the columns:
+  1      1
+  2      0.5
+  4      0.25
+...      ...
+*/
+scala> val out = new java.io.PrintWriter("out.txt")
+out: java.io.PrintWriter = java.io.PrintWriter@259aec72
+
+scala> for (i <- 0 to 20) {
+     | val pow = scala.math.pow(2, i)
+     | out.println(pow + "\t" + 1/pow)
+     | }
+
+scala> out.close
+
+scala> 
+/**
+ * $ cat out.txt 
+1.0	1.0
+2.0	0.5
+4.0	0.25
+8.0	0.125
+16.0	0.0625
+32.0	0.03125
+64.0	0.015625
+128.0	0.0078125
+256.0	0.00390625
+512.0	0.001953125
+1024.0	9.765625E-4
+2048.0	4.8828125E-4
+4096.0	2.44140625E-4
+8192.0	1.220703125E-4
+16384.0	6.103515625E-5
+32768.0	3.0517578125E-5
+65536.0	1.52587890625E-5
+131072.0	7.62939453125E-6
+262144.0	3.814697265625E-6
+524288.0	1.9073486328125E-6
+1048576.0	9.5367431640625E-7
+*/
+
diff --git a/Chapter09.scala b/Chapter09.scala
@@ -55,4 +55,25 @@ scala> Source.fromURL("http://www.gutenberg.org/cache/epub/4809/pg4809.txt", "UT
 res7: Array[String] = Array(redistributing, Volunteers*****, council--Policy, Orange--Corrupt, government--Efforts, reform--Influence, Armenteros--Painful, retire--Secret, Philip--Ominous, persecution--Execution, Antwerp--Horrible, Protestants--Remonstrance, Titelmann--Obduracy, Philip--Council, Trent--Quarrel, envoys--Order, Netherlands--Opposition, measure--Reluctance, Spain--Violent, instructions--Remarkable, Orange--Apoplexy, Viglius--Temporary, Hopper--Departure, Cambray--Character, Archbishop--Egmont, Spain--Flattery, bribery--Council, Doctors--Vehement, --Proceedings, principality--Egmont's, persecution--Indignation, Egmont--Habitual, dissimulation, King--Reproof, Orange--Assembly, Brussels--Result, deliberations, Philip--Universal, Netherlands--New, heretics--Interview, subject-...
 scala> 
 
+/**
+ * 4. Write a Scala program that reads a text file containing only floating-point numbers. Print the sum, average, maximum, and minimum of the numbers in the file.
+ */
+scala> import scala.io.Source
+import scala.io.Source
+
+scala> val numbers = Source.fromFile("/Users/harit/Downloads/floating.txt", "UTF-8").getLines.map(_.toDouble).toArray
+numbers: Array[Double] = Array(3.14, 2.34, 1.54, 8.34)
+
+scala> numbers.min
+res9: Double = 1.54
+
+scala> numbers.max
+res10: Double = 8.34
+
+scala> numbers.sum
+res11: Double = 15.36
+
+scala> numbers.sum/numbers.size
+res12: Double = 3.84
+
 
diff --git a/Chapter09.scala b/Chapter09.scala
@@ -45,3 +45,14 @@ scala> out.flush
 
 scala> out.close
 
+/**
+ *“3. Write a Scala code snippet that reads a file and prints all words with more than 12 characters to the console. Extra credit if you can do this in a single line.
+ */
+scala> import scala.io.Source
+import scala.io.Source
+
+scala> Source.fromURL("http://www.gutenberg.org/cache/epub/4809/pg4809.txt", "UTF-8").mkString.split("\\s").filter(_.length > 12)
+res7: Array[String] = Array(redistributing, Volunteers*****, council--Policy, Orange--Corrupt, government--Efforts, reform--Influence, Armenteros--Painful, retire--Secret, Philip--Ominous, persecution--Execution, Antwerp--Horrible, Protestants--Remonstrance, Titelmann--Obduracy, Philip--Council, Trent--Quarrel, envoys--Order, Netherlands--Opposition, measure--Reluctance, Spain--Violent, instructions--Remarkable, Orange--Apoplexy, Viglius--Temporary, Hopper--Departure, Cambray--Character, Archbishop--Egmont, Spain--Flattery, bribery--Council, Doctors--Vehement, --Proceedings, principality--Egmont's, persecution--Indignation, Egmont--Habitual, dissimulation, King--Reproof, Orange--Assembly, Brussels--Result, deliberations, Philip--Universal, Netherlands--New, heretics--Interview, subject-...
+scala> 
+
+
diff --git a/Chapter09.scala b/Chapter09.scala
@@ -0,0 +1,47 @@
+/**
+ * 1. Write a Scala code snippet that reverses the lines in a file (making the last line the first one, and so on).
+ */
+scala> import scala.io.Source
+import scala.io.Source
+
+scala> val source = Source.fromURL("http://www.gutenberg.org/cache/epub/4809/pg4809.txt", "UTF-8")
+source: scala.io.BufferedSource = non-empty iterator
+
+scala> source.getLines.toArray.reverse
+res10: Array[String] = Array(*END THE SMALL PRINT! FOR PUBLIC DOMAIN EBOOKS*Ver.02/11/02*END*, "", express permission.], they hardware or software or any other related product without, used in any sales of Project Gutenberg eBooks or other materials be, Michael S. Hart.  Project Gutenberg is a TradeMark and may not be, when distributed free of all fees.  Copyright (C) 2001, 2002 by, [Portions of this eBook's header and trailer may be reprinted only, "", hart@pobox.com, software or other items, please contact Michael Hart at:, If you are interested in contributing scanning equipment or, "", "Project Gutenberg Literary Archive Foundation.", Money should be paid to the:, public domain materials, or royalty free copyright licenses., The Project gratefully accepts contributions of money, tim...
+scala> 
+
+/**
+ * 2. Write a Scala program that reads a file with tabs, replaces each tab with spaces so that tab stops are at n-column boundaries, and writes the result to the same file.
+ */
+
+// File (with tabs)
+/**
+ * $ cat ~/Downloads/fileWithTabs.txt 
+    a	b	c
+    d	e	f
+ */
+scala> val tabPattern = """\t""".r
+tabPattern: scala.util.matching.Regex = \t
+
+scala> val source = Source.fromFile("/Users/harit/Downloads/fileWithTabs.txt")
+source: scala.io.BufferedSource = non-empty iterator
+
+scala> val lines = source.getLines.toArray
+lines: Array[String] = Array(a	b	c, d	e	f)
+
+scala> lines(0)
+res13: String = a	b	c
+
+scala> import java.io.PrintWriter
+import java.io.PrintWriter
+
+scala> val out = new PrintWriter("/Users/harit/Downloads/fileWithTabs.txt")
+out: java.io.PrintWriter = java.io.PrintWriter@106e6dfe
+
+scala> for(line <- replacedLines) {out.println(line)}
+
+scala> out.flush
+
+scala> out.close
+
diff --git a/Chapter06.scala b/Chapter06.scala
@@ -49,15 +49,15 @@ res60: Double = 25.4
   * 4. Define a Point class with a companion object so that you can construct 
   * Point instances as Point(3, 4), without using new.
   */
-  scala> :paste
+scala> :paste
 // Entering paste mode (ctrl-D to finish)
 
 object Point {
   def apply(x: Int, y: Int) = new Point(x,y)
 }
 
 class Point private(x:Int, y: Int) {
-  println(s"New Point Created (${x}, ${y}))")
+  override def toString = s"New Point Created (${x}, ${y}))"
 }
 
 // Exiting paste mode, now interpreting.
@@ -66,6 +66,24 @@ defined object Point
 defined class Point
 
 scala> Point(3,4)
-New Point Created (3, 4))
-res61: Point = Point@e042502
+res0: Point = New Point Created (3, 4))
 
+/**
+ * 5. Write a Scala application, using the App trait, that prints the command-line arguments 
+ * in reverse order, separated by spaces. For example, scala Reverse Hello World should print World Hello.”
+ */
+// Open a new file called MyApp.scala and paste the following contents
+object MyApp extends App {
+ if(args.length < 1) println("Provide enough arguments to print")
+ println(args.reverse.mkString(" "))
+}
+
+$ scalac MyApp.scala
+
+$ scala MyApp Hello World Scala
+Scala World Hello
+
+$ scala MyApp
+Provide enough arguments to print
+
+// Not attempting 6,7,8 (Enumeration)
diff --git a/Chapter06.scala b/Chapter06.scala
@@ -1,4 +1,71 @@
 /**
  * 1. Write an object Conversions with methods inchesToCentimeters, gallonsToLiters, and milesToKilometers.
  */
-
+scala> object Conversions {
+     |   def inchesToCentimeters(inches: Double): Double = 2.54 * inches
+     |   def gallonsToLiters(gallons: Double): Double = 3.78541 * gallons
+     |   def milesToKilometers(miles: Double): Double = 1.61 * miles
+     | }
+defined object Conversions
+
+scala> Conversions.inchesToCentimeters(10)
+res56: Double = 25.4
+
+scala> Conversions.gallonsToLiters(1)
+res57: Double = 3.78541
+
+scala> Conversions.milesToKilometers(7)
+res58: Double = 11.270000000000001
+
+/**
+ * 2. The preceding problem wasn’t very object-oriented. Provide a general superclass UnitConversion and define objects InchesToCentimeters, 
+ * GallonsToLiters, and MilesToKilometers that extend it.
+ */
+scala> abstract class UnitConversion {
+     |   def convert(input: Double): Double
+     | }
+defined class UnitConversion
+
+scala> object InchesToCentimeters extends UnitConversion {
+     |   def convert(input: Double) = 2.54 * input
+     |   def apply(input: Double) = convert(input)
+     | }
+defined object InchesToCentimeters
+
+scala> InchesToCentimeters(1)
+res59: Double = 2.54
+
+scala> InchesToCentimeters(10)
+res60: Double = 25.4
+
+/**
+ * 3. Define an Origin object that extends java.awt.Point. 
+ * Why is this not actually a good idea? (Have a close look at the methods of the Point class.)
+ */
+ // Not a good idea since it has setXXX methods and in singleton since everybody shares, anyone can
+ // change value causing trouble
+
+ /**
+  * 4. Define a Point class with a companion object so that you can construct 
+  * Point instances as Point(3, 4), without using new.
+  */
+  scala> :paste
+// Entering paste mode (ctrl-D to finish)
+
+object Point {
+  def apply(x: Int, y: Int) = new Point(x,y)
+}
+
+class Point private(x:Int, y: Int) {
+  println(s"New Point Created (${x}, ${y}))")
+}
+
+// Exiting paste mode, now interpreting.
+
+defined object Point
+defined class Point
+
+scala> Point(3,4)
+New Point Created (3, 4))
+res61: Point = Point@e042502
+
diff --git a/Chapter06.scala b/Chapter06.scala
@@ -0,0 +1,4 @@
+/**
+ * 1. Write an object Conversions with methods inchesToCentimeters, gallonsToLiters, and milesToKilometers.
+ */
+
diff --git a/Chapter04.scala b/Chapter04.scala
@@ -206,3 +206,29 @@ ftp.nonProxyHosts            |local|*.local|169.254/16|*.169.254/16
 sun.cpu.isalist              |
 res42: Iterable[Unit] = ArrayBuffer((), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), ())
 
+/**
+ * 8. Write a function minmax(values: Array[Int]) that returns a pair containing the smallest and largest values in the array.
+ */
+scala> def minmax(values: Array[Int]):(Int, Int) = (values.min, values.max)
+minmax: (values: Array[Int])(Int, Int)
+
+scala> minmax(Array(1, 100, -1, 20))
+res45: (Int, Int) = (-1,100)
+
+/**
+ * 9. Write a function lteqgt(values: Array[Int], v: Int) that returns a triple 
+ * containing the counts of values less than v, equal to v, and greater than v.
+ */
+scala> def lteqgt(values: Array[Int], v: Int): (Int, Int, Int) = (values.count(_ < v), values.count(_ == v), values.count(_ > v))
+lteqgt: (values: Array[Int], v: Int)(Int, Int, Int)
+
+scala> lteqgt(Array(0,0,1,1,1,2,2), 1)
+res47: (Int, Int, Int) = (2,3,2)
+
+/**
+ * 10. What happens when you zip together two strings, such as "Hello".zip("World")? Come up with a plausible use case.
+ */
+scala> "Hello".zip("World")
+res52: scala.collection.immutable.IndexedSeq[(Char, Char)] = Vector((H,W), (e,o), (l,r), (l,l), (o,d))
+
+// use-case? May be sum 2 arrays 
diff --git a/Chapter04.scala b/Chapter04.scala
@@ -121,5 +121,88 @@ weekdays: scala.collection.mutable.LinkedHashMap[String,Int] = Map(Monday -> 2,
 
 scala> weekdays
 res0: scala.collection.mutable.LinkedHashMap[String,Int] = Map(Monday -> 2, Tuesday -> 3, Sunday -> 1, Friday -> 6)
-
-
+
+/**
+ * 7. Print a table of all Java properties, like this:
+     java.runtime.name             | Java(TM) SE Runtime Environment
+     sun.boot.library.path         | /home/apps/jdk1.6.0_21/jre/lib/i386
+     java.vm.version               | 17.0-b16
+     java.vm.vendor                | Sun Microsystems Inc.
+     java.vendor.url               | http://java.sun.com/
+     path.separator                | :
+     java.vm.name                  | Java HotSpot(TM) Server VM
+     You need to find the length of the longest key before you can print the table.
+ */
+// https://stackoverflow.com/questions/32217170/how-to-have-width-between-values 
+scala> import scala.collection.JavaConversions.propertiesAsScalaMap
+import scala.collection.JavaConversions.propertiesAsScalaMap
+
+scala> val props: scala.collection.Map[String, String] = System.getProperties()
+props: scala.collection.Map[String,String] =
+Map(env.emacs -> "", java.runtime.name -> Java(TM) SE Runtime Environment, sun.boot.library.path -> /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib, java.vm.version -> 25.51-b03, gopherProxySet -> false, java.vm.vendor -> Oracle Corporation, java.vendor.url -> http://java.oracle.com/, path.separator -> :, java.vm.name -> Java HotSpot(TM) 64-Bit Server VM, file.encoding.pkg -> sun.io, user.country -> US, sun.java.launcher -> SUN_STANDARD, sun.os.patch.level -> unknown, java.vm.specification.name -> Java Virtual Machine Specification, user.dir -> /Users/harit, java.runtime.version -> 1.8.0_51-b16, java.awt.graphicsenv -> sun.awt.CGraphicsEnvironment, java.endorsed.dirs -> /Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk...
+
+scala> props.keys.map(_.length).max
+res24: Int = 29
+
+scala> for ((k,v) <- props) yield println(k.padTo(29, " ").mkString + "|" + v)
+env.emacs                    |
+java.runtime.name            |Java(TM) SE Runtime Environment
+sun.boot.library.path        |/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib
+java.vm.version              |25.51-b03
+gopherProxySet               |false
+java.vm.vendor               |Oracle Corporation
+java.vendor.url              |http://java.oracle.com/
+path.separator               |:
+java.vm.name                 |Java HotSpot(TM) 64-Bit Server VM
+file.encoding.pkg            |sun.io
+user.country                 |US
+sun.java.launcher            |SUN_STANDARD
+sun.os.patch.level           |unknown
+java.vm.specification.name   |Java Virtual Machine Specification
+user.dir                     |/Users/harit
+java.runtime.version         |1.8.0_51-b16
+java.awt.graphicsenv         |sun.awt.CGraphicsEnvironment
+java.endorsed.dirs           |/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/endorsed
+os.arch                      |x86_64
+java.io.tmpdir               |/var/folders/39/rrqhhzfn42bf7qcwqg2kywtr0000gn/T/
+line.separator               |
+
+java.vm.specification.vendor |Oracle Corporation
+os.name                      |Mac OS X
+sun.jnu.encoding             |UTF-8
+java.library.path            |/Users/harit/Library/Java/Extensions:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java:.
+java.specification.name      |Java Platform API Specification
+java.class.version           |52.0
+sun.management.compiler      |HotSpot 64-Bit Tiered Compilers
+os.version                   |10.10.4
+http.nonProxyHosts           |local|*.local|169.254/16|*.169.254/16
+user.home                    |/Users/harit
+user.timezone                |America/Los_Angeles
+scala.home                   |/usr/local/Cellar/scala/2.11.7/libexec
+java.awt.printerjob          |sun.lwawt.macosx.CPrinterJob
+file.encoding                |UTF-8
+java.specification.version   |1.8
+scala.usejavacp              |true
+java.class.path              |""
+user.name                    |harit
+java.vm.specification.version|1.8
+sun.java.command             |scala.tools.nsc.MainGenericRunner
+java.home                    |/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre
+sun.arch.data.model          |64
+user.language                |en
+java.specification.vendor    |Oracle Corporation
+awt.toolkit                  |sun.lwawt.macosx.LWCToolkit
+java.vm.info                 |mixed mode
+java.version                 |1.8.0_51
+java.ext.dirs                |/Users/harit/Library/Java/Extensions:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/ext:/Library/Java/Extensions:/Network/Library/Java/Extensions:/System/Library/Java/Extensions:/usr/lib/java
+sun.boot.class.path          |/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/sunrsasign.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_51.jdk/Contents/Home/jre/classes:/usr/local/Cellar/scala/2.11.7/libexec/lib/akka-actor_2.11-2.3.10.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/config-1.2.1.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/jline-2.12.1.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-actors-2.11.0.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-actors-migration_2.11-1.1.0.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-compiler.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-continuations-library_2.11-1.0.2.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-continuations-plugin_2.11.7-1.0.2.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-library.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-parser-combinators_2.11-1.0.4.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-reflect.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-swing_2.11-1.0.2.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scala-xml_2.11-1.0.4.jar:/usr/local/Cellar/scala/2.11.7/libexec/lib/scalap-2.11.7.jar
+java.vendor                  |Oracle Corporation
+file.separator               |/
+java.vendor.url.bug          |http://bugreport.sun.com/bugreport/
+sun.io.unicode.encoding      |UnicodeBig
+sun.cpu.endian               |little
+socksNonProxyHosts           |local|*.local|169.254/16|*.169.254/16
+ftp.nonProxyHosts            |local|*.local|169.254/16|*.169.254/16
+sun.cpu.isalist              |
+res42: Iterable[Unit] = ArrayBuffer((), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), ())
+
diff --git a/Chapter04.scala b/Chapter04.scala
@@ -86,3 +86,40 @@ scala> for(word <- words) {
 
 scala> wordCountSorted
 res2: scala.collection.immutable.SortedMap[String,Int] = Map("'Second -> 1, "1001 -> 1, "A -> 3, "All -> 2, "And -> 1, "Any -> 1, "But -> 1, "Defects," -> 1, "Do -> 1, "Draw -> 1, "Either -> 1, "First -> 5, "For -> 2, "From -> 1, "Here -> 1, "How -> 1, "In -> 2, "Information -> 1, "No -> 1, "Non-Exclusive" -> 1, "Not -> 1, "Open -> 1, "Pardon -> 1, "Pay-As-You-Leave" -> 1, "Plain -> 2, "Project -> 5, "Right -> 1, "Second -> 3, "Sell" -> 1, "Shoot -> 1, "Should -> 1, "Sky." -> 1, "Sneezing -> 1, "Speed-Pictures," -> 1, "Study -> 1, "The -> 10, "There -> 1, "There's -> 1, "Transference -> 1, "We -> 1, "Well, -> 1, "What -> 2, "Where -> 1, "Winter-Sports," -> 1, "Work -> 1, "_'How -> 1, "a -> 1, "arrow-points-to-the-scene-of-the-crime" -> 1, "author" -> 1, "barrels -> 1, "before -> 2, "by ...
+
+/**
+ * 5. Repeat the preceding exercise with a java.util.TreeMap that you adapt to the Scala API.
+ */
+scala> import java.util.TreeMap
+import java.util.TreeMap
+
+scala> var wordCountTreeMap = new TreeMap[String, Int]()
+wordCountTreeMap: java.util.TreeMap[String,Int] = {}
+
+scala> for(word <- words) {
+     |   val count = wordCountTreeMap.getOrDefault(word, 0)
+     |   wordCountTreeMap.put(word, count+1)
+     | }
+
+scala> wordCount
+wordCountSorted   wordCountTreeMap
+
+scala> wordCountTreeMap
+res7: java.util.TreeMap[String,Int] = {"'Second=1, "1001=1, "A=3, "All=2, "And=1, "Any=1, "But=1, "Defects,"=1, "Do=1, "Draw=1, "Either=1, "First=5, "For=2, "From=1, "Here=1, "How=1, "In=2, "Information=1, "No=1, "Non-Exclusive"=1, "Not=1, "Open=1, "Pardon=1, "Pay-As-You-Leave"=1, "Plain=2, "Project=5, "Right=1, "Second=3, "Sell"=1, "Shoot=1, "Should=1, "Sky."=1, "Sneezing=1, "Speed-Pictures,"=1, "Study=1, "The=10, "There=1, "There's=1, "Transference=1, "We=1, "Well,=1, "What=2, "Where=1, "Winter-Sports,"=1, "Work=1, "_'How=1, "a=1, "arrow-points-to-the-scene-of-the-crime"=1, "author"=1, "barrels=1, "before=2, "by=1, "cashed=1, "dead"=1, "deliver=1, "delivers=2, "eaten=1, "either=1, "film-eater."=1, "flivver"=1, "for=1, "fuzzy."=1, "get=1, "he=1, "heart-trouble."=1, "hot=1, "it's=1, "my...
+
+/**
+ * 6. Define a linked hash map that maps "Monday" to java.util.Calendar.MONDAY, and similarly for the other weekdays. Demonstrate that the elements are visited in insertion order.
+ */
+scala> import scala.collection.mutable.LinkedHashMap
+import scala.collection.mutable.LinkedHashMap
+
+scala> import java.util.Calendar._
+import java.util.Calendar._
+
+scala> val weekdays = LinkedHashMap[String, Int]("Monday" -> MONDAY, "Tuesday" -> TUESDAY, "Sunday" -> SUNDAY, "Friday" -> FRIDAY)
+weekdays: scala.collection.mutable.LinkedHashMap[String,Int] = Map(Monday -> 2, Tuesday -> 3, Sunday -> 1, Friday -> 6)
+
+scala> weekdays
+res0: scala.collection.mutable.LinkedHashMap[String,Int] = Map(Monday -> 2, Tuesday -> 3, Sunday -> 1, Friday -> 6)
+
+
diff --git a/Chapter04.scala b/Chapter04.scala
@@ -0,0 +1,88 @@
+/**
+ * 1. Set up a map of prices for a number of gizmos that you covet. 
+ * Then produce a second map with the same keys and the prices at a 10 percent discount.
+ */
+scala> val items = Map("Tesla" -> 80000, "iWatch" -> 700)
+items: scala.collection.immutable.Map[String,Int] = Map(Tesla -> 80000, iWatch -> 700)
+
+scala> for ((item, value) <- items) yield(item, value - (value * 0.1))
+res2: scala.collection.immutable.Map[String,Double] = Map(Tesla -> 72000.0, iWatch -> 630.0)
+
+/**
+ * 2. Write a program that reads words from a file. Use a mutable map to count how often each word appears.
+ */
+// source file: https://www.gutenberg.org/cache/epub/35709/pg35709.txt 
+scala> val words = scala.io.Source.fromFile("pg35709.txt").mkString.split("\\s+")
+words: Array[String] = Array(The, Project, Gutenberg, EBook, of, Making, Your, Camera, Pay,, by, Frederick, C., Davis, 
+This, eBook, is, for, the, use, of, anyone, anywhere, at, no, cost, and, with, almost, no, restrictions, whatsoever., 
+You, may, copy, it,, give, it, away, or, re-use, it, under, the, terms, of, the, Project, Gutenberg, License, included, 
+with, this, eBook, or, online, at, www.gutenberg.net, Title:, Making, Your, Camera, Pay, Author:, Frederick, C., Davis, 
+Release, Date:, March, 29,, 2011, [EBook, #35709], Language:, English, ***, START, OF, THIS, PROJECT, GUTENBERG, EBOOK, 
+MAKING, YOUR, CAMERA, PAY, ***, Produced, by, The, Online, Distributed, Proofreading, Team, at, http://www.pgdp.net, 
+(This, file, was, produced, from, images, generously, made, available, by, The, In... 
+
+scala> val wordCount = scala.collection.mutable.HashMap[String, Int]()
+wordCount: scala.collection.mutable.HashMap[String,Int] = Map()
+
+scala> for (word <- words) {
+     | val count = wordCount.getOrElse(word, 0)
+     | wordCount(word) = count + 1
+     | }
+
+scala> word
+wordCount   words
+
+scala> wordCount
+res1: scala.collection.mutable.HashMap[String,Int] = Map(arts -> 1, follow -> 3, request, -> 1, Lines. -> 1, 
+demand -> 7, 1.E.4. -> 1, PRODUCT -> 2, 470 -> 1, Chicago, -> 3, scenic -> 1, J2 -> 1, untrimmed -> 1, 
+photographs--not -> 1, basis. -> 1, "prints -> 1, instances. -> 1, Onion-Planter -> 1, trick -> 1, 
+illustrating -> 3, prefer. -> 1, detected -> 1, non-exclusive. -> 1, famous -> 1, Competition -> 2, 
+expense -> 1, created -> 2, renamed. -> 1, maggot -> 1, calendar-photographs, -> 1, widely-read -> 1, 
+Publisher, -> 1, producers -> 1, Shapes -> 1, ARTICLES -> 2, yearly -> 2, retoucher -> 1, satisfy -> 2, 
+agrees: -> 1, Gentleman_, -> 1, intellectual -> 2, hard -> 2, Porch. -> 1, sold.) -> 1, START -> 1, House -> 2, 
+welcome -> 1, Dealers' -> 1, ... -> 2, pasted -> 1, _Cosmopolitan_ -...
+
+/**
+ * 3. Repeat the preceding exercise with an immutable map.
+ */
+scala> val words = scala.io.Source.fromURL("https://www.gutenberg.org/cache/epub/35709/pg35709.txt").mkString.split("\\s+")
+words: Array[String] = Array(The, Project, Gutenberg, EBook, of, Making, Your, Camera, Pay,, by, Frederick, C., 
+Davis, This, eBook, is, for, the, use, of, anyone, anywhere, at, no, cost, and, with, almost, no, restrictions, 
+whatsoever., You, may, copy, it,, give, it, away, or, re-use, it, under, the, terms, of, the, Project, Gutenberg, 
+License, included, with, this, eBook, or, online, at, www.gutenberg.net, Title:, Making, Your, Camera, Pay, Author:, 
+Frederick, C., Davis, Release, Date:, March, 29,, 2011, [EBook, #35709], Language:, English, ***, START, OF, THIS, PROJECT, 
+GUTENBERG, EBOOK, MAKING, YOUR, CAMERA, PAY, ***, Produced, by, The, Online, Distributed, Proofreading, Team, at, 
+http://www.pgdp.net, (This, file, was, produced, from, images, generously, made, available, by, The, In...
+scala> var wordCount = Map[String, Int]()
+wordCount: scala.collection.immutable.Map[String,Int] = Map()
+
+scala> for (word <- words) {
+     | val count = wordCount.getOrElse(word, 0)
+     | wordCount = wordCount + (word -> (count + 1))
+     | }
+
+scala> wordCount
+res2: scala.collection.immutable.Map[String,Int] = Map("Should -> 1, serious -> 1, 
+Farm-buildings -> 1, container, -> 1, comply -> 6, forgotten -> 1, stop, -> 2, Spell -> 1, Washington, -> 6, 
+Advertises -> 1, rate -> 2, lights -> 1, submitted -> 1, engraver -> 3, generalize -> 2, Produced -> 2, Furniture: -> 1, 
+Redistributing -> 1, non-fictionist, -> 1, Archive/American -> 2, wiser -> 1, "snap-shooters" -> 1, action. -> 3, 6, -> 1, 
+supplementary -> 2, botany, -> 1, glean -> 1, locations -> 1, tenth, -> 1, Features -> 1, Advertising -> 1, Lens. -> 1, 
+trade, -> 1, SHAPE -> 2, particularly -> 1, bird-dogs, -> 1, used -> 24, Mo., -> 1, eye -> 1, PUNITIVE -> 1, striking -> 2, 
+gloss." -> 1, job--as -> 1, picture. -> 1, instance, -> 1, READ -> 1, Sets -> 1, Medical: -> 1, advertising-medium. -...
+scala> 
+
+/**
+ * 4. Repeat the preceding exercise with a sorted map, so that the words are printed in sorted order.
+ */
+scala> val words = scala.io.Source.fromURL("https://www.gutenberg.org/cache/epub/35709/pg35709.txt").mkString.split("\\s+")
+words: Array[String] = Array(The, Project, Gutenberg, EBook, of, Making, Your, Camera, Pay,, by, Frederick, C., Davis, This, eBook, is, for, the, use, of, anyone, anywhere, at, no, cost, and, with, almost, no, restrictions, whatsoever., You, may, copy, it,, give, it, away, or, re-use, it, under, the, terms, of, the, Project, Gutenberg, License, included, with, this, eBook, or, online, at, www.gutenberg.net, Title:, Making, Your, Camera, Pay, Author:, Frederick, C., Davis, Release, Date:, March, 29,, 2011, [EBook, #35709], Language:, English, ***, START, OF, THIS, PROJECT, GUTENBERG, EBOOK, MAKING, YOUR, CAMERA, PAY, ***, Produced, by, The, Online, Distributed, Proofreading, Team, at, http://www.pgdp.net, (This, file, was, produced, from, images, generously, made, available, by, The, In...
+scala> var wordCountSorted = scala.collection.immutable.SortedMap[String, Int]()
+wordCountSorted: scala.collection.immutable.SortedMap[String,Int] = Map()
+
+scala> for(word <- words) {
+     | val count = wordCountSorted.getOrElse(word, 0)
+     | wordCountSorted = wordCountSorted + (word -> (count + 1))
+     | }
+
+scala> wordCountSorted
+res2: scala.collection.immutable.SortedMap[String,Int] = Map("'Second -> 1, "1001 -> 1, "A -> 3, "All -> 2, "And -> 1, "Any -> 1, "But -> 1, "Defects," -> 1, "Do -> 1, "Draw -> 1, "Either -> 1, "First -> 5, "For -> 2, "From -> 1, "Here -> 1, "How -> 1, "In -> 2, "Information -> 1, "No -> 1, "Non-Exclusive" -> 1, "Not -> 1, "Open -> 1, "Pardon -> 1, "Pay-As-You-Leave" -> 1, "Plain -> 2, "Project -> 5, "Right -> 1, "Second -> 3, "Sell" -> 1, "Shoot -> 1, "Should -> 1, "Sky." -> 1, "Sneezing -> 1, "Speed-Pictures," -> 1, "Study -> 1, "The -> 10, "There -> 1, "There's -> 1, "Transference -> 1, "We -> 1, "Well, -> 1, "What -> 2, "Where -> 1, "Winter-Sports," -> 1, "Work -> 1, "_'How -> 1, "a -> 1, "arrow-points-to-the-scene-of-the-crime" -> 1, "author" -> 1, "barrels -> 1, "before -> 2, "by ...
diff --git a/Chapter03.scala b/Chapter03.scala
@@ -37,6 +37,7 @@ negative: Array[Int] = Array(-1, -10, 0, -12)
 
 scala> positive ++ negative
 res11: Array[Int] = Array(2, 3, 4, -1, -10, 0, -12)
+// better approach - https://stackoverflow.com/questions/32109281/produce-new-array-where-all-positive-comes-first-then-negative-or-zero-but-in-s
 
 /**
  * 5. How do you compute the average of an Array[Double]?

diff --git a/Chapter03.scala b/Chapter03.scala
@@ -23,3 +23,72 @@ res17: Array[Int] = Array(2, 1, 4, 3, 5)
 scala> (for {b <- a.grouped(2); c <- b.reverse} yield c).toArray
 res16: Array[Int] = Array(2, 1, 4, 3, 5)
 
+/**
+ * 4. Given an array of integers, produce a new array that contains all positive values 
+ * of the original array, in their original order, followed by all values that are zero or negative, 
+ * in their original order
+ */
+scala> val b = Array(-1, 2,3,4, -10, 0, -12)
+b: Array[Int] = Array(-1, 2, 3, 4, -10, 0, -12)
+
+scala> val(positive, negative) = b partition(_ > 0)
+positive: Array[Int] = Array(2, 3, 4)
+negative: Array[Int] = Array(-1, -10, 0, -12)
+
+scala> positive ++ negative
+res11: Array[Int] = Array(2, 3, 4, -1, -10, 0, -12)
+
+/**
+ * 5. How do you compute the average of an Array[Double]?
+ */
+scala> val doubleArray = Array(12.3, 12.3)
+doubleArray: Array[Double] = Array(12.3, 12.3)
+
+scala> doubleArray.sum/doubleArray.length
+res15: Double = 12.3
+
+/**
+ * 6. How do you rearrange the elements of an Array[Int] so that they appear in reverse sorted order? 
+ * How do you do the same with an ArrayBuffer[Int]?
+ */
+scala> val arrayInt = Array(1,2,3,4,5,6,7,8,9)
+arrayInt: Array[Int] = Array(1, 2, 3, 4, 5, 6, 7, 8, 9)
+
+scala> arrayInt sortWith(_>_)
+res32: Array[Int] = Array(9, 8, 7, 6, 5, 4, 3, 2, 1)
+
+scala> import scala.collection.mutable.ArrayBuffer
+import scala.collection.mutable.ArrayBuffer
+
+scala> val arrayBufferInt = ArrayBuffer(1,3,2,4,5,6,7,9,8)
+arrayBufferInt: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(1, 3, 2, 4, 5, 6, 7, 9, 8)
+
+scala> arrayBufferInt sortWith(_>_)
+res33: scala.collection.mutable.ArrayBuffer[Int] = ArrayBuffer(9, 8, 7, 6, 5, 4, 3, 2, 1)
+
+/**
+ * 7. Write a code snippet that produces all values from an array with duplicates removed. (Hint: Look at Scaladoc.)
+ */
+scala> val arrayWithDups = Array(2,2,4,5,6,6,3,3,1,1,1,1,0)
+arrayWithDups: Array[Int] = Array(2, 2, 4, 5, 6, 6, 3, 3, 1, 1, 1, 1, 0)
+
+scala> arrayWithDups.distinct
+res35: Array[Int] = Array(2, 4, 5, 6, 3, 1, 0)
+
+/* Not Attempting 08 */
+
+/**
+ * 9. Make a collection of all time zones returned by java.util.TimeZone.getAvailableIDs that are in America. 
+ * Strip off the "America/" prefix and sort the result.
+ */
+scala> java.util.TimeZone.getAvailableIDs filter(t => t.contains("America/")) map (t => t.split('/') last) sortWith(_ < _)
+warning: there was one feature warning; re-run with -feature for details
+res45: Array[String] = Array(Adak, Anchorage, Anguilla, Antigua, Araguaina, Aruba, Asuncion, Atikokan, Atka, Bahia, Bahia_Banderas, 
+Barbados, Belem, Belize, Beulah, Blanc-Sablon, Boa_Vista, Bogota, Boise, Buenos_Aires, Buenos_Aires, Cambridge_Bay, Campo_Grande, 
+Cancun, Caracas, Catamarca, Catamarca, Cayenne, Cayman, Center, Chicago, Chihuahua, ComodRivadavia, Coral_Harbour, Cordoba, Cordoba, 
+Costa_Rica, Creston, Cuiaba, Curacao, Danmarkshavn, Dawson, Dawson_Creek, Denver, Detroit, Dominica, Edmonton, Eirunepe, El_Salvador, 
+Ensenada, Fort_Wayne, Fortaleza, Glace_Bay, Godthab, Goose_Bay, Grand_Turk, Grenada, Guadeloupe, Guatemala, Guayaquil, Guyana, Halifax, 
+Havana, Hermosillo, Indianapolis, Indianapolis, Inuvik, Iqaluit, Jamaica, Jujuy, Jujuy, Juneau, Knox, Knox_IN, Kralendijk, La_Paz, L...
+scala> 
+
+/** Not attempting 10 */
diff --git a/Chapter03.scala b/Chapter03.scala
@@ -15,4 +15,11 @@ scala> val a = Array(1, 2, 3, 4, 5)
 a: Array[Int] = Array(1, 2, 3, 4, 5)
 
 scala> a.grouped(2).flatMap(_.reverse).toArray
-res17: Array[Int] = Array(2, 1, 4, 3, 5)
+res17: Array[Int] = Array(2, 1, 4, 3, 5)
+
+/**
+ * 3. Repeat the preceding assignment, but produce a new array with the swapped values. Use for/yield.
+ */
+scala> (for {b <- a.grouped(2); c <- b.reverse} yield c).toArray
+res16: Array[Int] = Array(2, 1, 4, 3, 5)
+
diff --git a/Chapter03.scala b/Chapter03.scala
@@ -0,0 +1,18 @@
+/**
+ * 1. Write a code snippet that sets a to an array of n random integers between 0 (inclusive) and n (exclusive)
+ */
+scala> def randomInRange(n:Int) = for(i <- 0 to n) yield Random.nextInt(n)
+randomInRange: (n: Int)scala.collection.immutable.IndexedSeq[Int]
+
+scala> randomInRange(100)
+res7: scala.collection.immutable.IndexedSeq[Int] = Vector(68, 47, 1, 20, 35, 93, 53, 24, 75, 46, 23, 61, 98, 62, 60, 38, 82, 69, 10, 82, 96, 30, 14, 50, 20, 42, 44, 11, 31, 18, 70, 13, 25, 77, 85, 89, 55, 45, 16, 44, 13, 50, 71, 58, 86, 16, 7, 79, 60, 31, 79, 52, 56, 86, 31, 85, 32, 84, 14, 54, 79, 56, 7, 68, 62, 87, 77, 4, 47, 28, 36, 23, 88, 19, 28, 41, 47, 3, 92, 88, 29, 22, 52, 8, 14, 76, 83, 45, 42, 45, 36, 77, 50, 12, 89, 28, 70, 97, 35, 70, 32)
+
+/**
+ * 2. Write a loop that swaps adjacent elements of an array of integers. For example, Array(1, 2, 3, 4, 5) becomes Array(2, 1, 4, 3, 5).
+ */
+ // http://stackoverflow.com/a/10160082/379235
+scala> val a = Array(1, 2, 3, 4, 5)
+a: Array[Int] = Array(1, 2, 3, 4, 5)
+
+scala> a.grouped(2).flatMap(_.reverse).toArray
+res17: Array[Int] = Array(2, 1, 4, 3, 5)
diff --git a/Chapter02.scala b/Chapter02.scala
@@ -124,4 +124,32 @@ scala> prod("")
 res5: Long = 0
 
 scala> prod("Hello")
-res6: Long = 9415087488
+res6: Long = 9415087488
+
+/**
+ * 10. Write a function that computes xn, where n is an integer. Use the following recursive definition:
+ * • xn = y2 if n is even and positive, where y = xn / 2.
+ * • xn = x·xn – 1 if n is odd and positive.
+ * • x0 = 1.
+ * • xn = 1 / x–n if n is negative.
+ * Don’t use a return statement.
+*/
+scala> def pow(x:Int, n:Int) = n match {
+     | case n if n > 0 && (n%2 == 0) => scala.math.pow(x, n/2)
+     | case n if n > 0 && (n%2 == 1) => x * scala.math.pow(x, n-1)
+     | case 0 => 1
+     | case n if n < 0 => 1/scala.math.pow(x, -n)
+     | }
+pow: (x: Int, n: Int)Double
+
+scala> pow(2, 4)
+res0: Double = 4.0
+
+scala> pow(2, 5)
+res1: Double = 32.0
+
+scala> pow(2, 0)
+res2: Double = 1.0
+
+scala> pow(2, -1)
+res3: Double = 0.5
diff --git a/Chapter02.scala b/Chapter02.scala
@@ -94,3 +94,34 @@ res19: Long = 9415087488
 /**
  * 7. Solve the preceding exercise without writing a loop. (Hint: Look at the StringOps Scaladoc.)
  */
+scala> "Hello".map(c => c.toLong).product
+res22: Long = 9415087488
+
+/**
+ * 8. Write a function product(s : String) that computes the product, as described in the preceding exercises.
+ */
+scala> def product(s:String) = s.map(c => c.toLong).product
+product: (s: String)Long
+
+scala> product("Hello")
+res23: Long = 9415087488
+
+/**
+ * 9. Make the function of the preceding exercise a recursive function.
+ */
+scala> def product(s:String, p:Long):Long = s.isEmpty match {
+     | case false => product(s.tail, p * s.head.toLong)
+     | case true => p
+     | }
+
+scala> def prod(s:String):Long = s.isEmpty match {
+     | case false => product(s, 1)
+     | case true => 0
+     | }
+prod: (s: String)Long
+
+scala> prod("")
+res5: Long = 0
+
+scala> prod("Hello")
+res6: Long = 9415087488
diff --git a/Chapter02.scala b/Chapter02.scala
@@ -12,4 +12,85 @@ scala> signum(0)
 res5: Int = 0
 
 scala> signum(-123)
-res6: Int = -1
+res6: Int = -1
+
+/**
+ * 2. What is the value of an empty block expression {}? What is its type?
+ */
+// Value is 'no value' and type is Unit
+scala> val empty = {}
+empty: Unit = ()
+
+scala> empty
+
+/**
+ * 3. Come up with one situation where the assignment x = y = 1 is valid in Scala. 
+ * (Hint: Pick a suitable type for x.)
+ */
+scala> var x: Any = _
+x: Any = null
+
+scala> var y: Int = _
+y: Int = 0
+
+scala> x = y = 1
+x: Any = ()
+
+scala> x
+res0: Any = ()
+
+scala> y
+res1: Int = 1
+
+/**
+ * 4. Write a Scala equivalent for the Java loop
+ * for (int i = 10; i >= 0; i--) System.out.println(i);
+ */
+// Range.by: Create a new range with the start and end values of this range and a new step.
+scala> for(i<- 10 to 0 by -1) println(i)
+10
+9
+8
+7
+6
+5
+4
+3
+2
+1
+0
+
+/**
+ * 5. Write a procedure countdown(n: Int) that prints the numbers from n to 0.
+ */
+scala> def countdown(n:Int) = for(i <- n to 0 by -1) println(i)
+countdown: (n: Int)Unit
+
+scala> countdown(10)
+10
+9
+8
+7
+6
+5
+4
+3
+2
+1
+0
+
+/**
+ * 6. Write a for loop for computing the product of the Unicode codes of all letters in a string. 
+ * For example, the product of the characters in "Hello" is 9415087488L.
+ */
+// IndexedSeq.product: Multiplies up the elements of this collection.
+// returns
+// the product of all elements in this sequence of numbers of type Int. 
+// Instead of Int, any other type T with an implicit Numeric[T] implementation can be used as element type of the sequence and as result type of product.
+// Examples of such types are: Long, Float, Double, BigInt.
+scala> (for(i <- "Hello") yield i.toLong).product
+res19: Long = 9415087488
+
+/**
+ * 7. Solve the preceding exercise without writing a loop. (Hint: Look at the StringOps Scaladoc.)
+ */
diff --git a/_Scala.For.The.Impatient.md → Scala.For.The.Impatient.md b/_Scala.For.The.Impatient.md → Scala.For.The.Impatient.md
diff --git a/Scala.For.The.Impatient.md → _Scala.For.The.Impatient.md b/Scala.For.The.Impatient.md → _Scala.For.The.Impatient.md
diff --git a/Scala For The Impatient.md → Scala.For.The.Impatient.md b/Scala For The Impatient.md → Scala.For.The.Impatient.md
diff --git a/ScalaForTheImpatient.md → Scala For The Impatient.md b/ScalaForTheImpatient.md → Scala For The Impatient.md
diff --git a/Chapter01.scala b/Chapter01.scala
@@ -0,0 +1,94 @@
+/**
+ * 2. In the Scala REPL, compute the square root of 3, and then square that value. By how much does the result differ from 3? (Hint: The res variables are your friend.)
+ */
+scala> math.sqrt(3)
+res1: Double = 1.7320508075688772
+
+scala> res1*res1
+res2: Double = 2.9999999999999996
+
+scala> 3 - res2
+res3: Double = 4.440892098500626E-16
+
+// 3. Are the res variables val or var?
+scala> res1 = 3
+<console>:11: error: reassignment to val
+       res1 = 3
+            ^
+
+/**
+ * 4. Scala lets you multiply a string with a number—try out "crazy" * 3 in the REPL. 
+ * What does this operation do? Where can you find it in Scaladoc?
+ */
+// StringOps.* : Return the current string concatenated n times.
+scala> "crazy "*3
+res6: String = "crazy crazy crazy "
+
+/**
+ * 5. What does 10 max 2 mean? In which class is the max method defined?
+ */
+ // Int.max: Returns this if this > that or that otherwise.
+scala> 10 max 2
+res7: Int = 10
+
+scala> 10.max(2)
+res8: Int = 10
+
+/**
+ * 6. Using BigInt, compute 21024.
+ */
+scala> BigInt(2) pow 1024
+res13: scala.math.BigInt = 179769313486231590772930519078902473361797697894230657273430081157732675805500963132708477322407536021120113879871393357658789768814416622492847430639474124377767893424865485276302219601246094119453082952085005768838150682342462881473913110540827237163350510684586298239947245938479716304835356329624224137216
+
+/**
+ * 7. What do you need to import so that you can get a random prime as probablePrime(100, Random), 
+ * without any qualifiers before probablePrime and Random?
+ */
+scala> import scala.util.Random
+import scala.util.Random
+
+scala> import scala.math.BigInt
+import scala.math.BigInt
+
+scala> import scala.math.BigInt.probablePrime
+import scala.math.BigInt.probablePrime
+
+scala> probablePrime(100, Random)
+res14: scala.math.BigInt = 931669304734992063893063804797
+
+/**
+ * 8. One way to create random file or directory names is to produce a random BigInt 
+ * and convert it to base 36, yielding a string such as "qsnvbevtomcj38o06kul". 
+ * Poke around Scaladoc to find a way of doing this in Scala.
+ */
+scala> probablePrime(100, Random) toString 36
+res15: String = 2mojnrl2508jtnu26t01
+
+/**
+ * 9. How do you get the first character of a string in Scala? The last character?
+ */
+scala> "Hello".head
+res20: Char = H
+
+scala> "Hello".last
+res21: Char = o
+
+/**
+ * 10. What do the take, drop, takeRight, and dropRight string functions do? 
+ * What advantage or disadvantage do they have over using substring?
+ */
+ // StringOps.drop: Selects all elements except first n ones.
+ // StringOps.dropRight: Selects all elements except last n ones.
+ // StringOps.take: Selects first n elements.
+ // StringOps.takeRight: Selects last n elements.
+scala> "Hello World!" take 6
+res22: String = "Hello "
+
+scala> "Hello World!" drop 6
+res23: String = World!
+
+scala> "Hello World!" takeRight 6
+res24: String = World!
+
+scala> "Hello World!" dropRight 6
+res25: String = "Hello "
diff --git a/Chapter02.scala b/Chapter02.scala
@@ -0,0 +1,15 @@
+/**
+ * 1. The signum of a number is 1 if the number is positive, –1 if it is negative, and 0 if it is zero. 
+ * Write a function that computes this value.
+ */
+scala> def signum(num:Int) = if (num > 0) 1 else if (num < 0) -1 else 0
+signum: (num: Int)Int
+
+scala> signum(10)
+res4: Int = 1
+
+scala> signum(0)
+res5: Int = 0
+
+scala> signum(-123)
+res6: Int = -1
diff --git a/ScalaForTheImpatient.md b/ScalaForTheImpatient.md
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+This gist will contain all the exercises from the book
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		@@ -0,0 +1 @@
		This gist will contain all the exercises from the book
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