gentleman851的博客

val x = Vector(1, 2, 3)x.sum // 6x.filter(_ > 1) // Vector(2, 3)x.map(_ * 2) // Vector(2, 4, 6)x.takeWhile(_ < 3) // Vector(1, 2)immutable ：ArraySeq属于IndexedSeq，底层数组实现，随机查找性能高，写操作需要线性时间LazyList属于L

def isBetween(a: Int, x: Int, y: Int) = a >= x && a <= y可以不带返回值类型但是最好写上val convert1to5 = new PartialFunction[Int, String] {val nums = Array(“one”, “two”, “three”, “four”, “five”)def apply(i: Int) = nums(i-1)def isDefinedAt(i: Int) = i &g

主构造器：VisibilityAccessor?Mutator?var是是val是否no var or val否否Adding the private keyword to var or val否否在类里面，无论上述条件如何，都可以访问和修改Case classes默认什么都不加的话是val，例如：case class Person(name: String)scala> val p = Person(“Dale Cooper”)

for i <- List(1, 2, 3) do println(i)fori <- 1 to 10if i > 3if i < 6doprintln(i)val listOfInts = fori <- 1 to 10if i > 3if i < 6yieldi * 10def isTrue(a: Matchable): Boolean = a matchcase 0 | “” => falsecase _ => tru

“1”.toByte // Byte = 1“1”.toShort // Short = 1“1”.toInt // Int = 1“1”.toLong // Long = 1“1”.toFloat // Float = 1.0“1”.toDouble // Double = 1.0“hello!”.toInt // java.lang.NumberFormatException“1”.toByteOption // Option[Byte

val h = "Hello"f"'$h%s'" // 'Hello'f"'$h%10s'" // ' Hello'f"'$h%-10s'" // 'Hello '