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new Iterator[String] { | |
def hasNext = resultSet.next() | |
def next() = resultSet.getString(1) | |
}.toStream |
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object x { | |
// stream a sql query | |
def sql( str:String ):Stream[ResultSet] = withStatement { s => | |
val rs = s executeQuery str | |
new Iterator[ResultSet] { def hasNext = rs.next ; def next = rs }.toStream | |
} | |
// loan a sql statement |
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println(scala.io.Source.fromFile("some.txt").mkString) |
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implicit def intWithTimes(n: Int) = new { | |
def times(f: => Unit) = 1 to n foreach {_ => f} | |
} | |
5 times { | |
println("Hello World") | |
} |
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trait ReflectionSugars{ | |
import scala.reflect.runtime.{universe => ru} | |
private lazy val universeMirror = ru.runtimeMirror(getClass.getClassLoader) | |
def companionOf[T](implicit tt: ru.TypeTag[T]) = { | |
val companionMirror = universeMirror.reflectModule(ru.typeOf[T].typeSymbol.companionSymbol.asModule) | |
companionMirror.instance | |
} | |
} |
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$ scala -Dscala.color |
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scala> val sqlc = new org.apache.spark.sql.SQLContext(sc) | |
scala> import sqlc.implicits._ //to implicitly convert an RDD to a DataFrame | |
scala> val df1 = sqlc.load("/home/....json","json") | |
scala> df1.printSchema | |
scala> df1.select("name").show | |
scala> df1.select("name", df1("age") + 1).show | |
scala> df1.filter(df1("age") > 10).show | |
scala> df1.groupBy("age").count().show | |
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def unless(expr: Boolean)(perform: ()=>Unit) { if(!expr) perform() } | |
unless(6 == 5) { ()=>println("Hello world") } |
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case object CONNECTION { | |
def unary_! = DISCONNECTION | |
def REMOVE = DISCONNECTION | |
} | |
case object DISCONNECTION | |
println(!CONNECTION == DISCONNECTION) //true | |
println((CONNECTION REMOVE) == DISCONNECTION) //true |
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; A REPL-based, annotated Seesaw tutorial | |
; Please visit https://github.com/daveray/seesaw for more info | |
; | |
; This is a very basic intro to Seesaw, a Clojure UI toolkit. It covers | |
; Seesaw's basic features and philosophy, but only scratches the surface | |
; of what's available. It only assumes knowledge of Clojure. No Swing or | |
; Java experience is needed. | |
; | |
; This material was first presented in a talk at @CraftsmanGuild in | |
; Ann Arbor, MI. |
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