R中的运算符重载和类定义:使用其他基础字段/语料库 [英] Operator overloading and class definition in R: Use a different base field/corpus

问题描述

((我在数学意义上使用了字段"一词 ； R已经使用的基本字段/语料库包括实数和复数.)

(I'm using the word "field" in the mathematical sense; base fields/corpora which R already uses include the real and complex numbers.)

我有兴趣允许其他一些基本字段/语料库(例如F₅，它是基数5中的模块化算术).为此，我需要

I'm interested in allowing some other base fields/corpora (like F₅, which is modular arithmetic in base 5). To do that I would need to

1. 定义新的数据类型
2. 重载相关运算符(+，*，也许还有更多)
3. 也许还有别的吗?例如，是否与其他功能集成?

1. define a new data type
2. overload the relevant operators (+, *, and maybe more)
3. maybe something else? e.g., integrate with other functionality?

那么，如何在R中定义新的数据类型或重载运算符?

So, how does one define a new data type or overload operators in R?

推荐答案

我发现Hadley Wickham的 devtools Wiki 是宝贵的资源R中的类入门.特别是，请阅读以下部分:

I found Hadley Wickham's devtools wiki an invaluable resource for getting started with classes in R. In particular, read the sections on:

• S3类
• S4类

• S3 classes
• S4 classes

此处是说明S3类中某些概念的起点.让我们将您的新类称为f5.至少，您可能希望创建以下方法:

Here is a starting point that illustrates some of the concepts in S3 classes. Let's call your new class f5. At a minimum, you would probably want to create methods for:

• 强制:as.f5
• 测试:is.f5
• 一些基本运算符:+.f5
• 处理打印的类:print.f5

• Coercion: as.f5
• Test: is.f5
• Some basic operators: +.f5
• A class to handle printing: print.f5

某些代码(使用包GLDEX中的digitsBase进行基本转换):

Some code (using digitsBase in package GLDEX to do the base conversion):

library(GLDEX)

as.f5 <- function(x){
  if(!inherits(x, "f5")) class(x) <- c("f5", class(x))
  x
}

is.f5 <- function(x){
  inherits(x, "f5")
}

`+.f5` <- function(e1, e2){
  NextMethod(e1, e2)
}

print.f5 <- function(x, ...){
  # Next line from ?GLDEX::digitsBase
  b2ch <- function(db) noquote(gsub("^0+(.{1,})$"," \1", 
                           apply(db, 2, paste, collapse = "")))

  cat("Base 5:\n")
  cat(b2ch(digitsBase(x, 5)))
  invisible(x)
}


x <- as.f5(0:10)
y <- as.f5(5)

x + y

Base 5:
10 11 12 13 14 20 21 22 23 24 30

这篇关于R中的运算符重载和类定义:使用其他基础字段/语料库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！