如何在 R 中实现 F# 的前向管道运算符? [英] how to implement F#'s forward pipe operator in R?

问题描述

如何在 R 中实现 F# 的前向管道运算符?运算符可以轻松链接一系列计算.例如，当你有一个输入data，想依次调用foo和bar函数，你可以这样写:

How can you implement F#'s forward pipe operator in R? The operator makes it possible to easily chain a sequence of calculations. For example, when you have an input data and want to call functions foo and bar in sequence, you can write:

data |> foo |> bar

而不是写bar(foo(data)).好处是您可以避免使用括号，并且计算的编写顺序与它们的执行顺序相同(从左到右).在 F# 中，运算符定义如下:

Instead of writing bar(foo(data)). The benefits are that you avoid some parentheses and the computations are written in the same order in which they are executed (left-to-right). In F#, the operator is defined as follows:

let (|>) a f = f a

看起来 %...% 可以用于二元运算符，但这如何工作?

It would appear that %...% can be used for binary operators, but how would this work?

推荐答案

我不知道它在任何实际用途中的表现如何，但这似乎 (?)参数函数...

I don't know how well it would hold up to any real use, but this seems (?) to do what you want, at least for single-argument functions ...

> "%>%" <- function(x,f) do.call(f,list(x))
> pi %>% sin
[1] 1.224606e-16
> pi %>% sin %>% cos
[1] 1
> cos(sin(pi))
[1] 1

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就其价值而言，截至目前(2021 年 12 月 3 日)，除了 magrittr/tidyverse 管道(%>%)之外，还有一个原生的R 中的管道 |>(以及可以在开发版本中启用的实验 => 运算符):参见 此处.

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For what it's worth, as of now (3 December 2021), in addition to the magrittr/tidyverse pipe (%>%), there also a native pipe |> in R (and an experimental => operator that can be enabled in the development version): see here, for example.

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