如何访问R中的帮助/文档.rd源文件？ [英] How to access the help/documentation .rd source files in R?

问题描述

在R中，一个非常整洁的功能是可以在工作区中的对象访问函数的源代码。

In R, one very neat feature is that the source code of functions is accessible as objects in the workspace.

因此，如果我想知道源代码例如， grep（）我可以直接在控制台中输入 grep 并阅读代码。

Thus, if I wanted to know the source code of, for example, grep() I can simply type grep into the console and read the code.

同样，我可以通过键入？grep grep 的文档>进入控制台。

Similarly, I can read the documentation for grep by typing ?grep into the console.

问题：如何获取函数文档的源代码？换句话说，我在哪里可以找到.rd文件？

我发现学习写好代码的源代码是学习习语的好方法。现在我想研究如何为一些非常具体的案例编写文档。我无法在R安装中找到任何基本R功能的文档文件。也许我一直在错误的地方。

I find studying the source of well-written code an excellent way of learning the idioms. Now I want to study how to write documentation for some very specific cases. I have not been able to find the documentation files for any of the base R functions in my R installation. Perhaps I have been looking in the wrong place.

推荐答案

似乎你可以从安装的R中提取Rd源。 m使用R-devel（2011-09-05 r56942）。

It seems you can extract the Rd sources from an installed R. I'm using R-devel (2011-09-05 r56942).

获取基础包的Rd数据库。

Get the database of Rd for the base package.

library(tools)
db <- Rd_db("base")

在Rd DB的名称中搜索grep.Rd，例如：

Search for "grep.Rd" in the names of the Rd DB, for example:

grep("grep.Rd", names(db), value = TRUE)
[1] "d:/murdoch/recent/R64/src/library/base/man/agrep.Rd"
[2] "d:/murdoch/recent/R64/src/library/base/man/grep.Rd" 

只需要grep的Rd对象。

Get just the Rd object for grep.

db[grep("/grep.Rd", names(db))]
$`d:/murdoch/recent/R64/src/library/base/man/grep.Rd`
\title{Pattern Matching and Replacement}
\name{grep}
\alias{grep}
\alias{grepl}
\alias{sub}
\alias{gsub}
\alias{regexpr}
\alias{gregexpr}
\alias{regexec}
\keyword{character}
\keyword{utilities}
\description{
\code{grep}, \code{grepl}, \code{regexpr} and \code{gregexpr} search
for matches to argument \code{pattern} within each element of a
character vector: they differ in the format of and amount of detail in
the results.

\code{sub} and \code{gsub} perform replacement of the first and all
matches respectively.
}\usage{
...
...

有从Rd对象获取组件的工具，因此您可以将关键字或名称的搜索精简，请参阅？Rd_db中的示例，然后尝试这样做。

There are tools for getting the components from the Rd objects, so you can refine searching to keywords or name, see examples in ?Rd_db and try this.

lapply(db, tools:::.Rd_get_metadata, "name")

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