DesignWeek1_.idea_misc.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
    <output url="file://$PROJECT_DIR$/out" />
  </component>
</project>

DesignWeek1_.idea_modules.xml

<?xml version="1.0" encoding="UTF-8"?>
<project version="4">
  <component name="ProjectModuleManager">
    <modules>
      <module fileurl="file://$PROJECT_DIR$/DesignWeek1.iml" filepath="$PROJECT_DIR$/DesignWeek1.iml" />
    </modules>
  </component>
</project>

DesignWeek1_DesignWeek1.iml

<?xml version="1.0" encoding="UTF-8"?>
<module type="JAVA_MODULE" version="4">
  <component name="NewModuleRootManager" inherit-compiler-output="true">
    <exclude-output />
    <content url="file://$MODULE_DIR$">
      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
    </content>
    <orderEntry type="inheritedJdk" />
    <orderEntry type="sourceFolder" forTests="false" />
    <orderEntry type="library" name="scala-sdk-2.11.8" level="application" />
  </component>
</module>

DesignWeek1_src_QueriesWithFor.sc

case class Book(title: String, authors: List[String])

val books: List[Book] = List(
  Book(title = "Structure and Interpretation of Computer Programs",
    authors = List("Abelson, Harald", "Sussman, Gerald J.")),
  Book(title = "Introduction to Functional Programming",
    authors = List("Bird, Richard", "Wadler, Phil")),
  Book(title = "Effective Java",
    authors = List("Bloch, Joshua")),
  Book(title = "Java Puzzlers",
    authors = List("Bloch, Joshua", "Gafter, Neal")),
  Book(title = "Programming in Scala",
    authors = List("Odersky, Martin", "Spoon, Lex", "Venners, Bill")))

for (b <- books; a <- b.authors if a startsWith "Bird,")
  yield b.title

for (b <- books if b.title.indexOf("Program") >= 0)
  yield b.title

for (b <- books if (b.title indexOf "Program") >= 0)
  yield b.title

{ for {
    b1 <- books
    b2 <- books
    if b1 != b2
    a1 <- b1.authors
    a2 <- b2.authors
    if a1 == a2
  } yield a1 }.distinct

val bookSet = books.toSet
for {
  b1 <- bookSet
  b2 <- bookSet
  if b1 != b2
  a1 <- b1.authors
  a2 <- b2.authors
  if a1 == a2
} yield a1