|NO.Z.00011|——————————|BigDataEnd|——|Hadoop&Scala.V11|——|Scala.v11|Scala编程|字符串插值器|

一、字符串插值器

### --- Scala 提供了三种字符串插值器：

~~~     s 插值器，对内嵌的每个表达式求值，对求值结果调用toString，替换掉字面量中的那些表达式
~~~     f 插值器，它除s插值器的功能外，还能进行格式化输出，在变量后用%指定输出格式，使用java.util.Formatter中给出的语法
~~~     raw 插值器，按照字符串原样进行输出      

### --- 字符串插值器类型

~~~     # s插值器
val subject = "Spark"
val str1 = s"Hello, $subject"
println(str1)
val arr = (1 to 10).toArray
val str2 = s"arr.length = ${arr.length}"
println(str2)
println(s"The answer is ${6*6}")      

### --- f插值器

val year=2020
val month=6
val day=9
println(s"$year-$month-$day")      

### --- yyyy-MM-dd，不足2位用0填充

println(f"$year-$month%02d-$day%02d")      

### --- raw插值器

println("a\nb\tc")
println(raw"a\nb\tc")
println("""a\nb\tc""")      

### --- 编程代码

package yanqi.cn.part01

/**
 * Scala中的插值器
 */
object InterpolatorDemo {
  def main(args: Array[String]): Unit = {
    //s插值器，可以通过$获取变量和表达式的值
    val subject = "Scala"
    val message = s"Hello,$subject"
    println(message)

    val array: Array[Int] = (1 to 10).toArray
    val str = s"array.length=${array.length}"
    println(str)

    println(s"${10 * 9}")

    //f插值器，用%指定输出格式
    val year=2020
    val month=8
    val day=9
    println(s"$year-$month-$day")
    //以yyyy-MM-dd的方式显示，不足2位用0填充
    println(f"$year-$month%02d-$day%02d")

    //raw插值器，将字符串按原样输出
    println("a\n\tc")
    println(raw"a\nb\tc")
    println("""a\nb\tc""")
  }
}      

### --- 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=52143: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.part01.InterpolatorDemo
Hello,Scala
array.length=10
90
2020-8-9
2020-08-09
a
    c
a\nb\tc
a\nb\tc

Process finished with exit code 0      

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