macos 一个错误 ['\+' is an unrecognized escape in the string starts at "\+" while 创建 R 包
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An error ['\+' is an unrecognized escape in character string starting "\+" while creating a R package
提问by Alex
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:
我尝试使用我创建的一些函数和脚本创建一个包（在 Mac 上使用 X11）。R CMD check 在做它的工作时，遇到了如下问题：
temp = trim(unlist(strsplit(lp.add(ranefterms[[i]]),
+ "\+")))
Error: '\+' is an unrecognized escape in character string starting "\+"
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 "\ +".
然而，最奇怪的是我的函数实际上没有“\ +”。相反，它有“\ \ +”（见下文）。所以我不知道为什么“\ \ +”被识别为“\ +”。
for(i in 1:n)
temp = trim(unlist(strsplit(lp.add(ranefterms[[i]]), '\+')))
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())
为了进一步挖掘，我查看了 Rcheck 文件夹中的 packageName-Ex.R 文件。原来，在检查过程中，所有的“\”都变成了“\”（比如strsplit()和grepl()等函数我需要的双斜线）
I wonder what may have been the cause of it. Sorry that I can't come up with a reproducible example...
我想知道可能是什么原因造成的。对不起，我不能想出一个可重现的例子......
采纳答案by Josh O'Brien
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 *.Rddocumentation files with a second backslash. (So, type \\to get \in the processed help file, and type \\\\to get \\.)
有问题的代码来自您的一个帮助文件的示例部分（这就是它以 结尾的原因packageName-Ex.R）。要修复它，只需*.Rd使用第二个反斜杠转义文档文件示例部分中的每个反斜杠。（因此，键入\\以获取\已处理的帮助文件，然后键入\\\\以获取\\。）
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):
除非它是逃过一劫，\被解释为特殊字符识别切片和标记宏（即命令状\author，\description，\bold，和\ldots）。引用 Duncan Murdoch 的Parsing Rd 文件（本主题的官方手册）：
The backslash \ is used as an escape character: \, \%, { and } remove the special meaning of the second character.
反斜杠\ 用作转义字符：\、\%、{ 和} 删除第二个字符的特殊含义。
As an example of what this looks like in practice, here is part of $R_SOURCE_HOME/src/library/base/man/grep.Rd, which is processed to create the help file you see when you type ?grepor ?gsub.
作为实际情况的示例，这里是 的一部分$R_SOURCE_HOME/src/library/base/man/grep.Rd，它被处理以创建您在键入?grep或时看到的帮助文件?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)
In the processed help file, it looks like this:
在处理后的帮助文件中，它是这样的：
## capitalizing
txt <- "a test of capitalizing"
gsub("(\w)(\w*)", "\U\1\L\2", txt, perl=TRUE)
gsub("\b(\w)", "\U\1", txt, perl=TRUE)
