如何跳过Scala中的可选参数? [英] How to skip optional parameters in Scala?

问题描述

给定以下带有可选参数的函数:

Given the following function with optional parameters:

def foo(a:Int = 1, b:Int = 2, c:Int = 3) ...

我想保留 a 的默认值，但仅通过位置分配(而不是通过 a)将新值传递给 b 和 c命名赋值)，这是以下任何一种语法都很好:

I want to keep the default value of a but pass new values to b and c only by positional assignment (rather than by a named assignment), that is any of the following syntaxes would be nice:

foo( , 5, 7)
foo(_, 5, 7)

Scala 可以实现类似的功能吗?

Is something like that possible with Scala?

推荐答案

没有办法跳过参数，但是你可以在调用你的 foo 方法时使用命名参数，例如:

There's no way to skip the parameters, but you can use named parameters when you call your foo method, for example:

// Call foo with b = 5, c = 7 and the default value for a
foo(b = 5, c = 7)

edit - 您专门询问了如何通过位置分配来做到这一点:这在 Scala 中是不可能的.

edit - You asked specifically how to do this by positional assignment: this is not possible in Scala.

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