list 遍历
var l = List(1,2,3,4,5)
l.foreach(i=>println(i))
map 遍历
var m = Map("tony" -> 80, "bob" -> 90)
m.foreach(kv => println(kv._1, kv._2))
val l = List("hive","hadoop","spark")
val books= l.map(s=>s.toUpperCase)
for(x <- books){
println(x)
}
val l = List("hive","hadoop","spark")
val books= l.flatMap(s=>s.toList)
for(x <- books){
println(x)
}
val l = List(1,2,3,4,5)
val result= l.filter(_%2==0)
println(result)
val l = List("hive","hadoop","spark")
val result= l.find(_ startsWith "h")
println(result)
val l = List("hive","hadoop","spark")
val result= l.exists(_ startsWith "h")
val l = List(1,2,3,4,5)
val result= l.reduce(_+_)
println(result)
val l = List(1,2,3,4,5)
val left= l.reduceLeft(_-_)
val l = List(1,2,3,4,5)
val right= l.reduceRight(_-_)
println(right)