Scala學習之字符串篇(四)：插值函數

在Scala中使用字符串插值函數，須要再字符串前加上字符"s"，而後再字符串中的每一個插值變量前加上「$」符號。

scala> val name = "Fred"
name: String = Fred

scala> val age = 18
age: Int = 18

scala> val weight = "200"
weight: String = 200

scala> println(s"$name is $age years old, and weights $weight pounds")
Fred is 18 years old, and weights 200 pounds

除了可使用變量外還能夠在字符串插值中使用表達式代碼。

scala> println(s"$age next year is ${age + 1}")
18 next year is 19
scala> println(s"$age is 18: ${age == 18}")
18 is 18: true

還能夠在插值表達式中使用對象。

scala> println(s"${student.name} is ${student.age} age years old.")
Fred is 18 age years old.

Scala爲咱們提供了更多的字符串插值函數，好比使用"f"能夠對插值打印格式進行控制，好比保留兩位小數。

scala> val weight = 200
weight: Int = 200

scala> println(f"$name is $age years old, and weights $weight%.2f pounds")
Fred is 18 years old, and weights 200.00 pounds

插值函數"raw"可以讓轉義字符失去意義。

scala> "a\nb"
res28: String =
a
b

scala> raw"a\nb"
res29: String = a\nb