How do you make a string in PHP with a backslash in it?
You have to escape all backslashes like "c:\\windows\\"
.
Short answer:
Use two backslashes.
Long answer:
You can sometimes use a single backslash, but sometimes you need two. When you can use a single backslash depends on two things:
- whether your string is surrounded by single quotes or double quotes and
- the character immediately following the backslash.
If you have a double quote string the backslash is treated as an escape character in many cases so it is best to always escape the backslash with another backslash:
$s = "foo\\bar"
In a single quoted string backslashes will be literal unless they are followed by either a single quote or another backslash. So to output a single backslash with a single quoted string you can normally write this:
$s = 'foo\bar'
But to output two backslashes in a row you need this:
$s = 'foo\\\\bar'
If you always use two backslashes you will never be wrong.
When the backslash \
does not escape the terminating quote of the string or otherwise create a valid escape sequence (in double quoted strings), then either of these work to produce one backslash:
$string = 'abc\def';
$string = "abc\def";
//
$string = 'abc\\def';
$string = "abc\\def";
When escaping the next character would cause a parse error (terminating quote of the string) or a valid escape sequence (in double quoted strings) then the backslash needs to be escaped:
$string = 'abcdef\\';
$string = "abcdef\\";
$string = 'abc\012';
$string = "abc\\012";