【Scala】高阶函数(3)

scala> val number = Seq(20, 40, 60)
number: Seq[Int] = List(20, 40, 60)

scala> val numbers = (x: Int) => x * 2
numbers: Int => Int = <function1>

scala> val result = number.map(numbers)
result: Seq[Int] = List(40, 80, 120)

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scala> val number = Seq(20, 40, 60)
number: Seq[Int] = List(20, 40, 60)

scala> val result = number.map(x => x * 2) 
result: Seq[Int] = List(40, 80, 120)

======================================

scala> val number = Seq(20, 40, 60)
number: Seq[Int] = List(20, 40, 60)

scala> val result = number.map(_ * 2)
result: Seq[Int] = List(40, 80, 120)

======================================

scala> def urlBuilder(ssl: Boolean, domain: String): (String, String) => String = {
     |   val schema = if (ssl) "https://" else "http://"
     |   (endpoint: String, query: String) => s"$schema$domain/$endpoint?$query"
     | }
urlBuilder: (ssl: Boolean, domain: String)(String, String) => String

scala> val domain = "www.example.com"
domain: String = www.example.com

scala> def getURL = urlBuilder(ssl=true, domain)
getURL: (String, String) => String

scala> val endpoint = "users"
endpoint: String = users

scala> val query = "id=1"
query: String = id=1

scala> val url = getURL(endpoint, query) 
url: String = https://www.example.com/users?id=1