|NO.Z.00026|——————————|BigDataEnd|——|Hadoop&Scala.V06|——|Scala.v06|数组元组|元组及操作|

一、元组及操作

### --- 元组及操作

~~~     Tuple，元组。Map是键值对的集合。对偶是元组的最简单形态；
~~~     元组是不同类型的值的集合，元组中的元素可以是不同的数据类型，元组在Scala中的应用非常广泛。

### --- 编程示例

~~~     # 报错，元组的元素个数上限是22个
val a = Tuple23(1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,0,1,2,3)

// 定义元组
val a = (1, 1.2, "ad", 'd')
val b = Tuple4(1, 1.2, "ad", 'd')
println(a==b)

// Tuple的访问形式比较特殊。元组的下标从1开始
a._1
a _2
a._3
a _4

// 从元组接收数据
val (a1, a2, a3, a4), a5 = a
val (b1, _, b2, _), b5 = a

// 遍历元组，第一种方式
for(x <- a.productIterator){
println(x)
}

// 遍历元组，第二种方式
a.productIterator.foreach(x => println(x))

### --- 编程代码

package yanqi.cn.part03

/**
 * Tuple元组，可以存放不同数据类型的元素
 * 元组的索引从1开始，不是从0开始
 * 元组在Scala中应用非常广泛，在Spark的源码中会见到很多元组。
 * 在Scala中，已经事先定义好了22个Tuple，从Tuple1~~Tuple22
 * 在Tuple22中，最多只能有22个元素
 */
object TupleDemo {
  def main(args: Array[String]): Unit = {
    //定义一个元组
    val tuple = (1, 2.5, "spark", 'a', true)
    val tuple2 = (1, 1.2, "scala", 'b')
    println(tuple == tuple2)

    println(tuple._3)

    //从元组中接收数据
    val (t1, t2, t3, t4), t5 = tuple2
    println(s"$t1  $t2  $t3  $t4")

    val (b1,_,b2,_),b5=tuple2
    println(s"$b1  $b2")

    //遍历元组
    for (t <- tuple.productIterator){
      println(t)
    }
    println("===========================")
    tuple.productIterator.foreach(println(_))

  }
}

### --- 编译打印

D:\JAVA\jdk1.8.0_231\bin\java.exe "-javaagent:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\lib\idea_rt.jar=55225:D:\IntelliJIDEA\IntelliJ IDEA 2019.3.3\bin" -Dfile.encoding=UTF-8 -classpath D:\JAVA\jdk1.8.0_231\jre\lib\charsets.jar;D:\JAVA\jdk1.8.0_231\jre\lib\deploy.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\access-bridge-64.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\cldrdata.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\dnsns.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\jaccess.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\jfxrt.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\localedata.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\nashorn.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunec.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunjce_provider.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunmscapi.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\sunpkcs11.jar;D:\JAVA\jdk1.8.0_231\jre\lib\ext\zipfs.jar;D:\JAVA\jdk1.8.0_231\jre\lib\javaws.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jce.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jfr.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jfxswt.jar;D:\JAVA\jdk1.8.0_231\jre\lib\jsse.jar;D:\JAVA\jdk1.8.0_231\jre\lib\management-agent.jar;D:\JAVA\jdk1.8.0_231\jre\lib\plugin.jar;D:\JAVA\jdk1.8.0_231\jre\lib\resources.jar;D:\JAVA\jdk1.8.0_231\jre\lib\rt.jar;E:\NO.Z.10000——javaproject\NO.Z.00002.Hadoop\ScalaPro\out\production\ScalaPro;D:\JAVA\scala-2.12.2\lib\scala-library.jar;D:\JAVA\scala-2.12.2\lib\scala-reflect.jar yanqi.cn.part03.TupleDemo
false
spark
1  1.2  scala  b
1  scala
1
2.5
spark
a
true
===========================
1
2.5
spark
a
true

Process finished with exit code 0

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Walter Savage Landor:strove with none,for none was worth my strife.Nature I loved and, next to Nature, Art:I warm'd both hands before the fire of life.It sinks, and I am ready to depart

                                                                                                                                                   ——W.S.Landor

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