I need to change "/" into "\" in my R code. I have something like this:
tmp <- paste(getwd(),"tmp.xls",sep="/")
so my tmp is c:/Study/tmp.xls
and I want it to be: c:\Study\tmp.xls
Is it possible to change it in R?
Update as per comments.
If this is simply to save the file, then as #sgibb suggested, you are better off using file.path():
file.path(getwd(), "tmp.xls")
Update 2: You want double back-slashes.
tmp is a string and if you want to have an actual backslash you need to escape it -- with a backslash.
However, when R interprets the double slashes (for example, when looking for a file with the path indicated by the string), it will treat the seemingly double slashes as one.
Take a look at what happens when you output the string with cat()
cat("c:\\Study\\tmp.xls")
c:\Study\tmp.xls
The second slash has "disappeared"
Original Answer:
in R, \ is an escape character, thus if you want to print it literally, you need to escape the escape character: \\. This is what you want to put in your paste statement.
You can also use .Platform$file.sep as your sep argument, which will make your code much more portable.
tmp <- paste(getwd(),"tmp.xls",sep=.Platform$file.sep)
If you already have a string you would like to replace, you can use
gsub("/", "\\", tmp, fixed=TRUE)
Related
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
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 \\
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
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%
My Solution is to define an RStudio snippet as follows:
snippet pp
"`r gsub("\\\\", "\\\\\\\\\\\\\\\\", readClipboard())`"
This snippet converts backslashes \ into double backslashes \\. The following version will work if you prefer to convert backslahes to forward slashes /.
snippet pp
"`r gsub("\\\\", "/", readClipboard())`"
Once your preferred snippet is defined, paste a path from the clipboard by typing p-p-TAB-ENTER (that is pp and then the tab key and then enter) and the path will be magically inserted with R friendly delimiters.
Replace back slashes \ with forward slashes / when running windows machine
I know this is really old, but if you are copying and pasting anyway, you can just use:
read.csv(readClipboard())
readClipboard() escapes the back-slashes for you. Just remember to make sure the ".csv" is included in your copy, perhaps with this:
read.csv(paste0(readClipboard(),'.csv'))
And if you really want to minimize your typing you can use some functions:
setWD <- function(){
setwd(readClipboard())
}
readCSV <- function(){
return(readr::read_csv(paste0(readClipboard(),'.csv')))
}
#copy directory path
setWD()
#copy file name
df <- readCSV()
Replacing backslash with forward slash worked for me on Windows.
The best way to deal with this in case of txt file which contains data for text mining (speech, newsletter, etc.) is to replace "\" with "/".
Example:
file<-Corpus(DirSource("C:/Users/PRATEEK/Desktop/training tool/Text Analytics/text_file_main"))
I think that R is reading the '\' in the string as an escape character. For example \n creates a new line within a string, \t creates a new tab within the string.
'\' will work because R will recognize this as a normal backslash.
readClipboard() works directly too. Copy the path into your clipboard
C:\Users\surfcat\Desktop\2006_dissimilarity.csv
Then
readClipboard()
appears as
[1] "C:\\Users\\surfcat\\Desktop\\2006_dissimilarity.csv"
A simple way is to use python.
in python terminal type
r"C:\Users\surfcat\Desktop\2006_dissimilarity.csv"
and you'll get back
'C:\Users\surfcat\Desktop\2006_dissimilarity.csv'
Example:
example <- "\\begin"
example <- gsub(pattern = "\\\\", replacement = "\\", example)
I know the backslashes need to be escaped, which is why they're duplicated in the gsub function. But this code returns the string "begin" devoid of any backslashes. I've also tried
example <- "\\begin"
example <- gsub(pattern = "\\", replacement = "\", example, fixed = TRUE)
But RStudio (and apparently StackOverflow!) really doesn't like that--it treats "" like an open quotation mark followed by an escaped close quotation mark, rather than treating it as a string of a single backslash.
How can I do this? For better context, I have a .txt file of .tex code (except that every backslash is duplicated) that I am trying to turn into a .tex file within an Rmd document.
I'd be happy to use an implementation using stringr, if that makes things easier.
I would like to ammend some .tex files from within R.
I read the file with readLines() but I cannot replace the following text.
tex <- "$\\times$"
new_tex <- gsub("$\\times$", "\\ $\\times$", tex)
new_tex
It seems that it cannot find the $\\times$
But even if it does, is it possible to write \ without escaping them?
Thank you in advance!
gsub uses regular expressions by default unless you set fixed=TRUE.
In regular expressions $ means the end of the sentence , that's why it does not work.
This, instead should work :
new_tex <- gsub("$\\times$", "\\ $\\times$", tex,fixed=TRUE)
About the backslash, no, you can't write a backslash without escaping it. Otherwise, for example, it would be impossible for the R interpreter, to distinguish between a tab \t and a "backslash + t".
Without fixed = TRUE:
gsub("\\$\\\\times\\$", "\\\\ $\\\\times\\$", tex)
[1] "\\ $\\times$"
Unfortunately you need a lot of backslashes because you need to escape pretty much everything.
I have read some questions and answers on this topic in stack overflow but still don't know how to solve this problem:
My purpose is to transform the file directory strings in windows explorer to the form which is recognizable in R, e.g. C:\Users\Public needs to be transformed to C:/Users/Public, basically the single back slash should be substituted with the forward slash. However the R couldn't store the original string "C:\Users\Public" because the \U and \P are deemed to be escape character.
dirTransformer <- function(str){
str.trns <- gsub("\\", "/", str)
return(str.trns)
}
str <- "C:\Users\Public"
dirTransformer(str)
> Error: '\U' used without hex digits in character string starting ""C:\U"
What I am actually writing is a GUI, where the end effect is, the user types or pastes the directory into a entry field, pushes a button and then the program will process it automatically.
Would someone please suggest to me how to solve this problem?
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.
dirTransformer <- function(str){
str.trns <- gsub("\\\\", "/", str)
return(str.trns)
}
str <- readline()
C:\Users\Public
dirTransformer(str)
I'm not sure how you intend the user to input the path into the GUI, but when using readline() and then typing C:\Users\Public unquoted, R reads that in as:
> str
[1] "C:\\Users\\Public"
We then want to replace "\\" with "/", but to escape the "\\" we need "\\\\" in the gsub.
I can't be sure how the input from the user is going to be read into R in your GUI, but R will most likely escape the \s in the string like it does when using the readline example. the string you're trying to create "C:\Users\Public" wouldn't normally happen.
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
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 \\
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
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%
My Solution is to define an RStudio snippet as follows:
snippet pp
"`r gsub("\\\\", "\\\\\\\\\\\\\\\\", readClipboard())`"
This snippet converts backslashes \ into double backslashes \\. The following version will work if you prefer to convert backslahes to forward slashes /.
snippet pp
"`r gsub("\\\\", "/", readClipboard())`"
Once your preferred snippet is defined, paste a path from the clipboard by typing p-p-TAB-ENTER (that is pp and then the tab key and then enter) and the path will be magically inserted with R friendly delimiters.
Replace back slashes \ with forward slashes / when running windows machine
I know this is really old, but if you are copying and pasting anyway, you can just use:
read.csv(readClipboard())
readClipboard() escapes the back-slashes for you. Just remember to make sure the ".csv" is included in your copy, perhaps with this:
read.csv(paste0(readClipboard(),'.csv'))
And if you really want to minimize your typing you can use some functions:
setWD <- function(){
setwd(readClipboard())
}
readCSV <- function(){
return(readr::read_csv(paste0(readClipboard(),'.csv')))
}
#copy directory path
setWD()
#copy file name
df <- readCSV()
Replacing backslash with forward slash worked for me on Windows.
The best way to deal with this in case of txt file which contains data for text mining (speech, newsletter, etc.) is to replace "\" with "/".
Example:
file<-Corpus(DirSource("C:/Users/PRATEEK/Desktop/training tool/Text Analytics/text_file_main"))
I think that R is reading the '\' in the string as an escape character. For example \n creates a new line within a string, \t creates a new tab within the string.
'\' will work because R will recognize this as a normal backslash.
readClipboard() works directly too. Copy the path into your clipboard
C:\Users\surfcat\Desktop\2006_dissimilarity.csv
Then
readClipboard()
appears as
[1] "C:\\Users\\surfcat\\Desktop\\2006_dissimilarity.csv"
A simple way is to use python.
in python terminal type
r"C:\Users\surfcat\Desktop\2006_dissimilarity.csv"
and you'll get back
'C:\Users\surfcat\Desktop\2006_dissimilarity.csv'