我有一个名为foo的脚本。R包含另一个脚本other。R,在同一个目录下:

#!/usr/bin/env Rscript
message("Hello")
source("other.R")

但我想让R找到另一个。R,不管当前工作目录是什么。

换句话说,就是foo。R需要知道自己的路径。我该怎么做呢?


当前回答

这个问题有一个简单的解决办法。这个命令:

script.dir <- dirname(sys.frame(1)$ofile)

返回当前脚本文件的路径。它在保存脚本后工作。

其他回答

请注意,getopt包提供了get_Rscript_filename函数,该函数使用与本文相同的解决方案,但已经在标准R模块中为您编写了该解决方案,因此您不必将“获取脚本路径”函数复制并粘贴到您编写的每个脚本中。

I would use a variant of @steamer25 's approach. The point is that I prefer to obtain the last sourced script even when my session was started through Rscript. The following snippet, when included on a file, will provided a variable thisScript containing the normalized path of the script. I confess the (ab)use of source'ing, so sometimes I invoke Rscript and the script provided in the --file argument sources another script that sources another one... Someday I will invest in making my messy code turns into a package.

thisScript <- (function() {
  lastScriptSourced <- tail(unlist(lapply(sys.frames(), function(env) env$ofile)), 1)

  if (is.null(lastScriptSourced)) {
    # No script sourced, checking invocation through Rscript
    cmdArgs <- commandArgs(trailingOnly = FALSE)
    needle <- "--file="
    match <- grep(needle, cmdArgs)
    if (length(match) > 0) {
      return(normalizePath(sub(needle, "", cmdArgs[match]), winslash=.Platform$file.sep, mustWork=TRUE))
    }
  } else {
    # 'source'd via R console
    return(normalizePath(lastScriptSourced, winslash=.Platform$file.sep, mustWork=TRUE))
  }
})()

只是在上面的答案的基础上,作为安全检查,您可以添加一个包装器,当sys.frame(1)失败时(如果interactive() == TRUE可能会失败),或者源脚本不在主脚本所期望的位置时,它会要求用户找到文件。

fun_path = tryCatch(expr = 
                      {file.path(dirname(sys.frame(1)$ofile), "foo.R")},
                    error = function(e){'foo.R'}
                    )
if(!file.exists(fun_path))
{
  msg = 'Please select "foo.R"'
  # ask user to find data
  if(Sys.info()[['sysname']] == 'Windows'){#choose.files is only available on Windows
    message('\n\n',msg,'\n\n')
    Sys.sleep(0.5)#goes too fast for the user to see the message on some computers
    fun_path  = choose.files(
      default = file.path(gsub('\\\\', '/', Sys.getenv('USERPROFILE')),#user
                          'Documents'),
      caption = msg
    )
  }else{
    message('\n\n',msg,'\n\n')
    Sys.sleep(0.5)#goes too fast for the user to see the message on some computers
    fun_path = file.choose(new=F)
  }
}
#source the function
source(file = fun_path, 
       encoding = 'UTF-8')

我喜欢这种方法:

this.file <- sys.frame(tail(grep('source',sys.calls()),n=1))$ofile
this.dir <- dirname(this.file)

我喜欢steamer25的解决方案,因为它似乎是最健壮的。然而,当在RStudio中调试时(在windows中),路径不会被正确设置。原因是,如果在RStudio中设置了断点,那么源文件将使用另一个“调试源”命令,该命令将脚本路径设置得稍微不同。下面是我目前正在使用的最终版本,它解释了调试时RStudio中的这种替代行为:

# @return full path to this script
get_script_path <- function() {
    cmdArgs = commandArgs(trailingOnly = FALSE)
    needle = "--file="
    match = grep(needle, cmdArgs)
    if (length(match) > 0) {
        # Rscript
        return(normalizePath(sub(needle, "", cmdArgs[match])))
    } else {
        ls_vars = ls(sys.frames()[[1]])
        if ("fileName" %in% ls_vars) {
            # Source'd via RStudio
            return(normalizePath(sys.frames()[[1]]$fileName)) 
        } else {
            # Source'd via R console
            return(normalizePath(sys.frames()[[1]]$ofile))
        }
    }
}