R流水线功能 [英] R Pipelining functions

问题描述

有没有一种方法可以在R中编写流水线函数，其中一个函数的结果立即传递到下一个?我来自F#，真的很喜欢这种功能，但是还没有找到如何在R中做到这一点.它应该很简单，但是我找不到如何做.在F#中，它看起来像这样:

Is there a way to write pipelined functions in R where the result of one function passes immediately into the next? I'm coming from F# and really appreciated this ability but have not found how to do it in R. It should be simple but I can't find how. In F# it would look something like this:

let complexFunction x =
     x |> square 
     |> add 5 
     |> toString

在这种情况下，输入将被平方，然后添加5，然后转换为字符串.我希望能够在R中做类似的事情，但不知道如何做.我一直在寻找如何做这样的事情，但没有遇到任何问题.我要用它来导入数据，因为通常我必须先将其导入然后进行过滤.现在，我分多个步骤执行此操作，并且确实希望能够像在F#中使用管道一样执行某些操作.

In this case the input would be squared, then have 5 added to it and then converted to a string. I'm wanting to be able to do something similar in R but don't know how. I've searched for how to do something like this but have not come across anything. I'm wanting this for importing data because I typically have to import it and then filter. Right now I do this in multiple steps and would really like to be able to do something the way you would in F# with pipelines.

推荐答案

我们可以使用功能包中的Compose来创建自己的二进制运算符，以执行与所需操作类似的操作

We can use Compose from the functional package to create our own binary operator that does something similar to what you want

# Define our helper functions
square <- function(x){x^2}
add5 <- function(x){x + 5}

# functional contains Compose
library(functional)

# Define our binary operator
"%|>%" <- Compose

# Create our complexFunction by 'piping' our functions
complexFunction <- square %|>% add5 %|>% as.character
complexFunction(1:5)
#[1] "6"  "9"  "14" "21" "30"


# previously had this until flodel pointed out
# that the above was sufficient
#"%|>%" <- function(fun1, fun2){ Compose(fun1, fun2) }

我想我们可以在不需要功能包的情况下从技术上做到这一点-但使用Compose进行此任务感觉很正确.

I guess we could technically do this without requiring the functional package - but it feels so right using Compose for this task.

"%|>%" <- function(fun1, fun2){
    function(x){fun2(fun1(x))}
}
complexFunction <- square %|>% add5 %|>% as.character
complexFunction(1:5)
#[1] "6"  "9"  "14" "21" "30"

这篇关于R流水线功能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！