Efficiently Convert Backslash to Forward Slash in R

Efficiently convert backslash to forward slash in R

In R, you've to escape the \ with \\ So, your path should be:

x <- "C:\\Users\\jd\\Documents\\folder\\file.txt"

To get that, you can do:

x <- readline()

then, at the prompt, paste your unmodified path (CTRL+V then ENTER)

Finally, to change \\ to / everywhere, you could use gsub, once again by escaping the \, but twice, as follows:

gsub("\\\\", "/", x)
# [1] "C:/Users/jd/Documents/folder/file.txt"

Why R uses forward slash (/) and not backslash (\) in file paths

Interesting question.

First off, the "forward slash" / is actually more common as it used by Unix, Linux, and macOS.

Second, the "backward slash" \ is actually somewhat painful as it is also an escape character. So whenever you want one, you need to type two in string: "C:\\TEMP".

Third, R on Windows knows this and helps! So you can you use a forward slash whereever you would use a backward slash: "C:/TEMP" works the same!

Fourth, you can have R compute the path for you and it will use use the separator: file.path("some", "dir").

So the short answer: R uses both on Windows and lets you pick whichever you find easier. But remember to use two backward slashes (unless you use the very new R 4.0.0 feature on raw strings which I'll skip for now).

Replacing Backward slash in R

You have the arguments in the wrong order and you need to escape the backslashes.

> stringr::str_replace("\\asd", "\\\\", "//")
[1] "//asd"

How to automatically handle strings/paths with backslashes?

You can use this hack. Suppose you had copied your path as mentioned then you could use

scan("clipboard", "character", quiet = TRUE)

scan reads the text copied from the clipboard and takes care about the backslashes. Then copy again what is returned from scan

Replace slash with a single backslash in R

The solution is to escape the escape character which means 4 '\' in the end.

cat(gsub('/', '\\\\', "file_path/file_name.txt"))

Look at the difference between your standard output with like 'print()' which escapes the escape character, or get the plain string by using 'cat()'.

str_replace_all(string = x, pattern = "/", replacement = "\\\\")
cat(str_replace_all(string = x, pattern = "/", replacement = "\\\\"))

Escaping backslash (\) in string or paths in R

From R 4.0.0 you can use r"(...)" to write a path as raw string constant, which avoids the need for escaping:

r"(E:\RStuff\test.r)"
# [1] "E:\\RStuff\\test.r"

There is a new syntax for specifying raw character constants similar to the one used in C++: r"(...)" with ... any character sequence not containing the sequence )". This makes it easier to write strings that contain backslashes or both single and double quotes. For more details see ?Quotes.

substitute single backslash in R

When you need to use a backslash in the string in R, you need to put double backslash. Also, when you use gsub("\\", "/", str), the first argument is parsed as a regex, and it is not valid as it only contains a single literal backslash that must escape something. In fact, you need to make gsub treat it as a plain text with fixed=TRUE.

However, you might want to use normalizePath, see this SO thread.

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