This question already has an answer here:
paste quotation marks into character string, within a loop
(1 answer)
Closed 5 years ago.
I have started learning R and am trying to create vector as below:
c(""check"")
I need the output as : "check". But am getting syntax error. How to escape the quotes while creating a vector?
As #juba mentioned, one way is directly escaping the quotes.
Another way is to use single quotes around your character expression that has double quotes in it.
> x <- 'say "Hello!"'
> x
[1] "say \"Hello!\""
> cat(x)
say "Hello!"
Other answers nicely show how to deal with double quotes in your character strings when you create a vector, which was indeed the last thing you asked in your question. But given that you also mentioned display and output, you might want to keep dQuote in mind. It's useful if you want to surround each element of a character vector with double quotes, particularly if you don't have a specific need or desire to store the quotes in the actual character vector itself.
# default is to use "fancy quotes"
text <- c("check")
message(dQuote(text))
## “check”
# switch to straight quotes by setting an option
options(useFancyQuotes = FALSE)
message(dQuote(text))
## "check"
# assign result to create a vector of quoted character strings
text.quoted <- dQuote(text)
message(text.quoted)
## "check"
For what it's worth, the sQuote function does the same thing with single quotes.
Use a backslash :
x <- "say \"Hello!\""
And you don't need to use c if you don't build a vector.
If you want to output quotes unescaped, you may need to use cat instead of print :
R> cat(x)
say "Hello!"
Related
unable to enclose "hey" in double quotes within a string . I am unable to get output as Hey "Hey"
ad<- "hey"
fd<- paste("Hey","",ad,sep="")
The dQuote function is made for this:
dQuote("hey")
# [1] "\"hey\""
Note that depending on the OS and your environment, it might add "fancy quotes" (angled/directional double-quotes). They may look good but if you want to reuse the results as a string in R, it won't work because R does not recognize its smart quotes as string-boundaries. You can explicitly disable it with dQuote(., q=FALSE). (The default is FALSE on windows except for the Rgui console, but I believe the default is TRUE elsewhere.)
Depending on your need, you may also like shQuote due to its escaping of existing embedded quotes:
cat(dQuote('"hey" there'), "\n")
# ""hey" there" # may not be right
cat(shQuote('"hey" there'), "\n")
# "\"hey\" there"
though whether that is correct depends on your needs; shQuote was designed for shell-quoting/escaping.
Ultimately in your example, I think you would use
ad <- "Hey"
paste("Hey", dQuote(ad))
# [1] "Hey \"Hey\""
Double quotes can be added with
paste0('"', "Hey", '"')
#[1] "\"Hey\""
Or
sprintf('"%s"', "Hey")
#[1] "\"Hey\""
Note that R displays strings with double quotes (") so to show double quotes as part of string it escapes it with backslash \. To see actual string you may use cat on it.
cat(paste0('"', "Hey", '"'))
#"Hey"
You can write raw strings like:
r"{"Hey"}"
r'{"Hey"}'
[1] "\"hey\""
See ?Quotes
Raw character constants are also available using a syntax similar to the one used in C++: r"(...)" with ... any character sequence, except that it must not contain the closing sequence )". The delimiter pairs [] and {} can also be used, and R can be used in place of r. For additional flexibility, a number of dashes can be placed between the opening quote and the opening delimiter, as long as the same number of dashes appear between the closing delimiter and the closing quote.
There is a vector of strings that looks like the following (text with two or more substrings in quotation marks):
vec <- 'ab"cd"efghi"j"kl"m"'
The text within the first pair of quotation marks (cd) contains a useful identifier (cd is the desired output). I have been studying how to use regular expressions but I haven't learned how to find the first and second occurrences of something like quotation marks.
Here's how I have been getting cd:
tmp <- strsplit(vec,split="")[[1]]
paste(tmp[(which(tmp=='\"')[1]+1):(which(tmp=='\"')[2]-1)],collapse="")
"cd"
My question is, is there another way to find "cd" using regular expressions? in order to learn more how to use them. I prefer base R solutions but will accept an answer using packages if that's the only way. Thanks for your help.
Match everything except " then capture everything upto next " and replace captured group by itself.
gsub( '[^"]*"([^"]*).*', '\\1', vec)
[1] "cd"
For detailed explanation of regex you can see this demo
This question already has an answer here:
"'\w' is an unrecognized escape" in grep
(1 answer)
Closed 1 year ago.
I would like to find and replace tabular instances by tabularx. I tried with gsub but it seems to enter me into a world of escaping pain. Following other questions and answers I find fixed=TRUE which is the best I so far have. The code snippet below almost works, \B is unrecognized. If I escape it twice I get \BEGIN as output!
texText <- '\begin{tabular}{rl}\begin{tabular}{rll}'
texText <- gsub("\begin{tabular}{rl}", "\BEGIN{tabular}{rll}", texText, fixed=TRUE)
I'm using BEGIN as my test to see what is happening. This is before I get to tackling the question of what goes on in the brackets {rl} {ll} {rrl} etc. Ideally I'm looking for a regex that would output:
\begin{tabularx}{rX}\begin{tabularx}{rlX}
That is the final column is replaced by X.
Try using proper escaping:
texText <- "\begin{tabular}{rl}\begin{tabular}{rll}"
output <- gsub("\begin\\{tabular\\}", "\begin{tabularx}", texText)
output
[1] "\begin{tabularx}{rl}\begin{tabularx}{rll}"
A literal backslash requires two backslashes, and also metacharacters such as { and } require two backslashes.
I'm working with the following code:
Y_Columns <- c("Y.1.1")
paste('{"ImportId":"', Y_Columns, '"}', sep = "")
The paste function produces the following output:
"{\"ImportId\":\"Y.1.1\"}"
How do I get the paste function to omit the \? Such that, the output is:
"{"ImportId":"Y.1.1"}"
Thank you for your help.
Note: I did do a search on SO to see if there were any Q's that asked "what is an escape character in R". But I didn't review all the 160 answers, only the first 20.
This is one way of demonstrating what I wrote in my comment:
out <- paste('{"ImportId":"', Y_Columns, '"}', sep = "")
out
#[1] "{\"ImportId\":\"Y.1.1\"}"
?print
print(out,quote=FALSE)
#[1] {"ImportId":"Y.1.1"}
Both R and regex patterns use escape characters to allow special characters to be displayed in print output or input. (And sometimes regex patterns need to have doubled escapes.) R has a few characters that need to be "escaped" in certain situation. You illustrated one such situation: including double-quote character inside a result that will be printed with surrounding double-quotes. If you were intending to include any single quotes inside a character value that was delimited by single quotes at the time of creation, they would have needed to be escaped as well.
out2 <- '\'quoted\''
nchar(out2)
#[1] 8 ... note that neither the surround single-quotes nor the backslashes get counted
> out2
[1] "'quoted'" ... and the default output quote-char is a double-quote.
Here's a good Q&A to review:How to replace '+' using gsub() function in R
It has two answers, both useful: one shows how to double escape a special character and the other shows how to use teh fixed argument to get around that requirement.
And another potentially useful Q&A on the topic of handling Windows paths:
File path issues in R using Windows ("Hex digits in character string" error)
And some further useful reading suggestions: Look at the series of help pages that start with capital letters. (Since I can never remember which one has which nugget of essential information, I tried ?Syntax first and it has a "See Also" list of essential reading: Arithmetic, Comparison, Control, Extract, Logic, NumericConstants, Paren, Quotes, Reserved. and I then realized what I wanted to refer you to was most likely ?Quotes where all the R-specific escape sequence letters should be listed.
This question already has answers here:
Remove quotes from a character vector in R
(11 answers)
Closed 6 years ago.
I would like to be able to copy and paste the output in R console without always having to remove these tags and quotes
print('love')
[1] "love"
What I require
print('love')
love
Note: I also want to remove the [1] not only the double quotes.
You could use the cat function, it will indeed print your string without parenthesis:
cat('love')
#### love
See the help page ?cat
Outputs the objects, concatenating the representations. cat performs
much less conversion than print.
You might also use print with the quote argument:
print("love", quote=FALSE)
#### [1] love
That way, you still get the [1]
See also this thread: https://stackoverflow.com/a/5218361/3871924