File path issues in R using Windows ("Hex digits in character string" error)

I run R on Windows, and have a csv file on the Desktop. I load it as follows,

x<-read.csv("C:\Users\surfcat\Desktop\2006_dissimilarity.csv",header=TRUE)

but the R gives the following error message

Error: '\U' used without hex digits in character string starting "C:\U"

So what's the correct way to load this file. I am using Vista

Solution 1:

replace all the \ with \\.

it's trying to escape the next character in this case the U so to insert a \ you need to insert an escaped \ which is \\

Solution 2:

Please do not mark this response as correct as smitec has already answered correctly. I'm including a convenience function I keep in my .First library that makes converting a windows path to the format that works in R (the methods described by Sacha Epskamp). Simply copy the path to your clipboard (ctrl + c) and then run the function as pathPrep(). No need for an argument. The path is printed to your console correctly and written to your clipboard for easy pasting to a script. Hope this is helpful.

pathPrep <- function(path = "clipboard") {
    y <- if (path == "clipboard") {
        readClipboard()
    } else {
        cat("Please enter the path:\n\n")
        readline()
    }
    x <- chartr("\\", "/", y)
    writeClipboard(x)
    return(x)
}

Solution 3:

Solution

Try this: x <- read.csv("C:/Users/surfcat/Desktop/2006_dissimilarity.csv", header=TRUE)

Explanation

R is not able to understand normal windows paths correctly because the "\" has special meaning - it is used as escape character to give following characters special meaning (\n for newline, \t for tab, \r for carriage return, ..., have a look here ).

Because R does not know the sequence \U it complains. Just replace the "\" with "/" or use an additional "\" to escape the "\" from its special meaning and everything works smooth.

Alternative

On windows, I think the best thing to do to improve your workflow with windows specific paths in R is to use e.g. AutoHotkey which allows for custom hotkeys:

• define a Hotkey, e.g. Cntr-Shift-V
• assigns it an procedure that replaces backslashes within your Clipboard with slaches ...
• when ever you want to copy paste a path into R you can use Cntr-Shift-V instead of Cntr-V
• Et-voila

AutoHotkey Code Snippet (link to homepage)

^+v::
StringReplace, clipboard, clipboard, \, /, All 
SendInput, %clipboard%