Questions tagged [backslash]

The backslash character \ (not to be confused with slash /) is used in many languages as an escape character to modify the meaning of the following character. It is also the directory separator in file paths under DOS and Windows.

The backslash character \ is a mirror version of the slash character /, created for use in computing. Its meaning depends on the context.

  • In many languages, \ followed by a character that has a special meaning makes the next character lose its special meaning. This is especially true inside string literals and regular expressions : for example, in many languages, "a\\b\"" represents the 4-character string a\b".
  • Sometimes \ gives the next character a special meaning. This is mostly the case when \ is followed by a letter or digit in a string literal, where it can be used to specify a control character or other special character. For example, \n specifies a newline in many languages, and \123 often specifies the character whose octal value is 123 (but note that some languages have different rules).
  • In DOS and Windows , the \ character is the directory (folder) separator in file paths. For example, c:\windows\cmd.exe is the file called cmd.exe in the directory called windows at the root of the c: drive.
  • In (La)TeX , \ starts a command name.
  • In Haskell , \ introduces a lambda expression .
991 questions
45
votes
8 answers

How do I add slashes to a string in Javascript?

Just a string. Add \' to it every time there is a single quote.
TIMEX
  • 259,804
  • 351
  • 777
  • 1,080
41
votes
4 answers

How can I put an actual backslash in a string literal (not use it for an escape sequence)?

I have this code: import os path = os.getcwd() final = path +'\xulrunner.exe ' + path + '\application.ini' print(final) I want output like: C:\Users\me\xulrunner.exe C:\Users\me\application.ini But instead I get an error that looks…
esafwan
  • 17,311
  • 33
  • 107
  • 166
39
votes
2 answers

sh read command eats backslashes in input?

Perhaps easiest to explain with an example: $ echo '\&|' \&| $ echo '\&|' | while read in; do echo "$in"; done &| It seems that the read command is interpreting the backslashes in the input as escapes and is removing them. I need to process a file…
Jeremy Huiskamp
  • 5,186
  • 5
  • 26
  • 19
35
votes
2 answers

Java regular expression value.split("\\."), "the back slash dot" divides by character?

From what I understand, the backslash dot (\.) means one character of any character? So because backslash is an escape, it should be backslash backslash dot ("\\.") What does this do to a string? I just saw this in an existing code I am working…
Nap
  • 8,096
  • 13
  • 74
  • 117
34
votes
5 answers

Escaping backslash in string - javascript

I need to show the name of the currently selected file (in element). Everything is fine, the only problem is I'm getting this kind of string "C:\fakepath \typog_rules.pdf" (browset automatically puts this as value for the input…
Max
  • 1,149
  • 3
  • 10
  • 20
32
votes
5 answers

Weird backslash substitution in Ruby

I don't understand this Ruby code: >> puts '\\ <- single backslash' # \ <- single backslash >> puts '\\ <- 2x a, because 2 backslashes get replaced'.sub(/\\/, 'aa') # aa <- 2x a, because two backslashes get replaced so far, all as expected. but if…
Peter
  • 127,331
  • 53
  • 180
  • 211
31
votes
6 answers

Backslashes in single quoted strings vs. double quoted strings

If I add a backslash+space to the start of double and single quoted strings, I get different results: "\ text" '\ text' In the output for the double quoted string I see only a space. In the output for the single quoted string I see…
Tucker
  • 323
  • 1
  • 3
  • 5
31
votes
3 answers

How to print out a backslash in LaTeX

I want to write a backslash character to a text file using LaTeX. The first line of code below declares a variable 'file' which describes the file 'myfile.out'. The second line opens the file and the third one tries do write a backslash '\' to the…
Giovanni Funchal
  • 8,934
  • 13
  • 61
  • 110
28
votes
2 answers

How to escape a backslash in R?

I'm working in R and having troubles escaping the backslash. I am using the library stringr. install.packages("stringr", repos='http://cran.us.r-project.org') library("stringr") I would like to do str = str_replace_all(str, "\", "") So I tried str…
Paul Fournel
  • 10,807
  • 9
  • 40
  • 68
27
votes
7 answers

Java replace issues with ' (apostrophe/single quote) and \ (backslash) together

I seem to be having issues. I have a query string that has values that can contain single quotes. This will break the query string. So I was trying to do a replace to change ' to \'. Here is a sample code: "This is' it".replace("'", "\'"); The…
derekmw
  • 375
  • 1
  • 5
  • 13
26
votes
1 answer

How to replace backslash with double backslash?

I'm trying to replace backslashes in my string with two backslashes like so: str.gsub!("\\", "\\\\") But, it doesn't do anything. I'm confused...
Tony R
  • 11,224
  • 23
  • 76
  • 101
26
votes
5 answers

Why is '\x' invalid in Python?

I was experimenting with '\' characters, using '\a\b\c...' just to enumerate for myself which characters Python interprets as control characters, and to what. Here's what I found: \a - BELL \b - BACKSPACE \f - FORMFEED \n - LINEFEED \r - RETURN \t…
PaulMcG
  • 62,419
  • 16
  • 94
  • 130
25
votes
1 answer

Windows shell string operations (changing backslash to slash)

I need to write a script that takes the current path (%~dp0), transforms backslashes into forward slashes and passes it further to some command. Due to the environment I'm working in the only option that I have is windows shell (not Powershell where…
Matthias Hryniszak
  • 3,099
  • 3
  • 36
  • 51
24
votes
2 answers

Why does pressing Ctrl-backslash result in core dump?

When I'm in a python application (the python shell, for instance), pressing ctrl + \ results in >>> Quit (core dumped) Why is this, and how can I avoid this? It is very inconvenient if application bails out whenever I press ctrl + \ by accident.
chtenb
  • 14,924
  • 14
  • 78
  • 116
23
votes
2 answers

What is the purpose of a backslash at the end of a line?

Just found the following module import in a Python code: from sqlalchemy.ext.declarative import declarative_base,\ AbstractConcreteBase I am curious about the backslash \ at the end of the first line. What's the purpose of it? Wouldn't it be…
fedorqui
  • 275,237
  • 103
  • 548
  • 598
1
2
3
65 66