How to escape backslashes in R string
r single backslash in string
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invalid regular expression '\', reason 'trailing backslash'
I'm writing strings to a file using R:
> x1="\\str" > x2="\\\str" Error: '\s' is an unrecognized escape in character string starting "\\\s" > x2="\\\\str" > write(file='test',c(x1,x2))
When I open the file named
test, I see this:
If I want to get a string containing 5 backslashes, should I write 10 backslashes, like this?
[...] If I want to get a string containing 5
\,should i write 10
Yes, you should. To write a single
\ in a string, you write it as
This is because the
\ is a special character, reserved to escape the character that follows it. (Perhaps you recognize
\n as newline.) It's also useful if you want to write a string containing a single
". You write it as
The reason why
\\\str is invalid, is because it's interpreted as
\\ (which corresponds to a single
\) followed by
\s, which is not valid, since "escaped
s" has no meaning.
Escape sequences, How do I remove an escape character from a string in Python? Inside those quotes, you can create special characters using \ as an escape character. For example, denotes new line or \" can be used to enter a " without R thinking it's the end of the string. Since \ is an escape character, you need a way to enter an actual . This is done by using \\. Escaping the escape!
Have a read of this section about character vectors.
In essence, it says that when you enter character string literals you enclose them in a pair of quotes (" or '). Inside those quotes, you can create special characters using \ as an escape character.
For example, \n denotes new line or \" can be used to enter a " without R thinking it's the end of the string. Since \ is an escape character, you need a way to enter an actual . This is done by using \\. Escaping the escape!
2.4.1 String literals, a backslash within a regular expression within a string in R. Presumably the string renders \ as a single , which regex thinks is an escape They will be displayed by print (and by the REPL that you see in an interactive session) with the escape-backslash, but using cat you cant determine that they are not really in there as backslashes. Further proof: > nchar("\"")  1 You can use either cat or print with quote=FALSE in you want to display the value as it really exists internally:
Note that the doubling of backslashes is because you are entering the string at the command line and the string is first parsed by the R parser. You can enter strings in different ways, some of which don't need the doubling. For example:
> tmp <- scan(what='') 1: \\\\\str 2: Read 1 item > print(tmp)  "\\\\\\\\\\str" > cat(tmp, '\n') \\\\\str >
How can I remove the ANSI escape sequences from a string in , Backslash \ in string. Dear R community, is there any way to include a backslash in a charakter string without meaning some escape sequence Backslash \ in string Dear R community, is there any way to include a backslash in a charakter string without meaning some escape sequence? E.g. i need a string like: a <- '\hline' Error: '\h' is an unrecognized escape in character string starting "\h" to include some latex code in a xtable object, but I only mange to do: a <- '\\hline' which
What does "\r" do in the following script?, String literals may optionally be prefixed with a letter `r' or `R'; such strings are called raw strings and use different rules for backslash escape sequences. Replace single backslash in R. Ask Question Asked 5 years, If it was meant to represent the string "this\is\my\string", you have to escape the backslashes.
Backslash headache in str_replace() · Issue #394 · STAT545-UBC , Escaping a character not in the following table is an error. Single quotes need to be escaped by backslash in single-quoted strings, and double quotes in double- [R] Find and replace backslashes XXXX; Dan Abner. You only need to escape it if you are writing a literal string in R code. Duncan Murdoch The. Duncan Murdoch:
R help - Backslash \ in string, When an 'r' or 'R' prefix is present, a character following a backslash is included in the string without change, and all backslashes are left in the string. For example Further reading: Escaping a backslash with a backslash in R produces 2 backslashes in a string, not 1. To use special characters in a regular expression the simplest method is usually to escape them with a backslash, but as noted above, the backslash itself needs to be escaped.
- No equivalent of Python's "raw strings" , as in: