错误['\ +'是无法识别的以'\ +'开头的字符串.在创建R包时 [英] An error ['\+' is an unrecognized escape in character string starting "\+" while creating a R package

问题描述

我尝试使用一些我创建的功能和脚本(在Mac上使用X11)创建一个软件包. R CMD检查在执行工作时遇到以下问题:

I tried to create a package using some functions and scripts I created (using X11 on a Mac). While R CMD check was doing its work, it encountered a problem as follows:

temp = trim(unlist(strsplit(lp.add(ranefterms[[i]]), 
+                     "\+")))
Error: '\+' is an unrecognized escape in character string starting "\+"

但是，最奇怪的是我的函数实际上没有"\ +".相反，它具有"\ \ +"(请参见下文).所以我不知道为什么"\ \ +"被识别为"\ +".

The oddest thing, however, is that my function actually does NOT have "\ +". Instead, it has "\ \ +" (see below). So I don't know why "\ \ +" is recognized as "\ +".

for(i in 1:n)
   temp = trim(unlist(strsplit(lp.add(ranefterms[[i]]), '\\+')))

为了进一步探讨，我查看了Rcheck文件夹中的packageName-Ex.R文件.事实证明，在检查过程中所有的"\ \"都已更改为"\"(例如，strsplit()和grepl()之类的函数需要双斜杠

To dig a little further, I looked at the packageName-Ex.R file in the Rcheck folder. As it turned out, all the "\ \"s have been changed to "\" in the checking process (e.g., the double slashes I need for functions such as strsplit() and grepl())

我想知道是什么原因造成的.抱歉，我无法提供可重复的示例...

I wonder what may have been the cause of it. Sorry that I can't come up with a reproducible example...

推荐答案

有问题的代码来自您一个帮助文件的示例"部分(这就是为什么它以packageName-Ex.R结尾)的原因.要解决此问题，只需在*.Rd文档文件的示例"部分中的每个反斜杠转义第二个反斜杠即可. (因此，键入\\以获得处理后的帮助文件中的\，然后键入\\\\以获得\\.)

The offending code comes from the Examples section of one of your help files (which is why it ends up in packageName-Ex.R). To fix it, just escape each of the backslashes in the Examples sections of your *.Rd documentation files with a second backslash. (So, type \\to get \ in the processed help file, and type \\\\ to get \\.)

除非将其转义，否则\会被解释为一个特殊字符，用于标识分段和标记宏(即\author，\description，\bold和\ldots之类的命令).引用邓肯·默多克(Duncan Murdoch)的 解析Rd文件 (该主题的官方手册):

Unless it's escaped, \ is interpreted as a special character that identifies sectioning and mark-up macros (i.e. commands like \author, \description, \bold, and \ldots). Quoting from Duncan Murdoch's Parsing Rd files (the official manual for this topic):

反斜杠\用作转义字符:\，\％，{和} 删除第二个字符的特殊含义.

The backslash \ is used as an escape character: \, \%, { and } remove the special meaning of the second character.

作为实际情况的一个示例，这是$R_SOURCE_HOME/src/library/base/man/grep.Rd的一部分，该内容被处理以创建您在键入?grep或?gsub时看到的帮助文件.

As an example of what this looks like in practice, here is part of $R_SOURCE_HOME/src/library/base/man/grep.Rd, which is processed to create the help file you see when you type ?grep or ?gsub.

## capitalizing
txt <- "a test of capitalizing"
gsub("(\\\\w)(\\\\w*)", "\\\\U\\\\1\\\\L\\\\2", txt, perl=TRUE)
gsub("\\\\b(\\\\w)",    "\\\\U\\\\1",       txt, perl=TRUE)

在已处理的帮助文件中，它看起来像这样:

In the processed help file, it looks like this:

 ## capitalizing
 txt <- "a test of capitalizing"
 gsub("(\\w)(\\w*)", "\\U\\1\\L\\2", txt, perl=TRUE)
 gsub("\\b(\\w)",    "\\U\\1",       txt, perl=TRUE)

这篇关于错误['\ +'是无法识别的以'\ +'开头的字符串.在创建R包时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！