34.scala编程思想笔记——基于类型的模式匹配
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可以基于值的模式匹配，还可以按照值的类型来匹配。
例如：
import com.atomicscala.AtomicTest._
def acceptAnything(x:Any):String = {
x match {
cases:String => "A String: " + s
case i:Intif(i < 20) =>
s"AnInt Less than 20: $i"
case i:Int=> s"Some Other Int: $i"
casep:Person => s"A person ${p.name}"
case _=> "I don't know what that is!"
}
}
acceptAnything(5) is
"An IntLess than 20: 5"
acceptAnything(25) is "Some Other Int: 25"
acceptAnything("Some text") is
"A String: Some text"
case class Person(name:String)
val bob = Person("Bob")
acceptAnything(bob) is "A person Bob"
acceptAnything(Vector(1, 2, 5)) is
"I don't know what that is!"
执行如下：
An Int Less than 20: 5
Some Other Int: 25
A String: Some text
A person Bob
I don't know what that is!
其中acceptAnything的参数类型Any.
Any 允许任何类型的参数。
Match表达式会查找String,Int或我们自己的类型Person.
注意下划线作用是通配符，用来匹配任何值都不匹配的对象。
