Scala 中的 toString 函数
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toString function in Scala
提问by sarthak
I'm new to Scala, I was reading about scala from the following source: http://docs.scala-lang.org/tutorials/tour/classes
我是 Scala 的新手，我正在从以下来源阅读有关 Scala 的信息：http: //docs.scala-lang.org/tutorials/tour/classes
It had the following code:
它有以下代码：
class Point(var x: Int, var y: Int) {
def move(dx: Int, dy: Int): Unit = {
x = x + dx
y = y + dy
}
override def toString: String =
"(" + x + ", " + y + ")"
}
object Classes {
def main(args: Array[String]) {
val pt = new Point(1, 2)
println(pt)
pt.move(10, 10)
println(pt)
}
}
The output is:
输出是：
(1, 2)
(11, 12)
I wanted to ask how did the println(pt)function printed the result (1,2)? Should we not call pt.toString()to print the result as shown?
我想问一下println(pt)函数是怎么打印结果的(1,2)？我们不应该打电话pt.toString()来打印如图所示的结果吗？
回答by Tzach Zohar
There's an overload of printlnthat accepts a value of type Any(in Predef.scala):
有一个println接受类型值的重载Any（在Predef.scala 中）：
def println(x: Any) = Console.println(x)
Deep inside, it calls x.toString()to get the string to print.
在内部，它调用x.toString()获取要打印的字符串。
