Scala下划线最小功能 [英] Scala underscore minimal function

问题描述

让我们为这个问题创造一个价值:

Let's create a value for the sake of this question:

val a = 1 :: Nil

现在，我可以证明匿名函数可以写成这样的速记形式:

now, I can demonstrate that the anonymous functions can be written in shorthand form like this:

a.map(_*2)

是否可以编写此函数的简写?:

is it possible to write a shorthand of this function?:

a.map((x) => x)

我的解决方案不起作用:

my solution doesn't work:

a.map(_)

推荐答案

你的第一个速记表格也可以写成无点

Your first shorthand form can also be written point-free

a map (2*)

由于乘法是可交换的.

至于(x) =>x，你需要 identity 函数.这是在 Predef 中定义的并且是通用的，因此您可以确定它是类型安全的.

As for (x) => x, you want the identity function. This is defined in Predef and is generic, so you can be sure that it's type-safe.

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