raw escape in python except last char

Question

Why in python I can't use:

r"c:\"

Answer 1

Use "c:/" or "c:\\". Raw string literals are for escaping escape-sequences, not for including literal backslashes, though they do work that way, except in this exact case.

Answer 2

Its a known case I think, better use "c:\\" for that case.

Answer 3

From the documentation

... a raw string cannot end in a single backslash (since the backslash would escape the following quote character).

Answer 4

When a string must contain the same quote character with with it's started, escaping that character is the only available workaround -- so the design alternative was either to make raw-string literals physically unable to contain their leading quote character, or keep the "backlash escapes" convention, even in string literals, just for quote characters.

Since raw-string literals were designed for handy representation of regular expression patterns (not for DOS / Windows paths!-), and in RE patterns a trailing backslash is never necessary, the design decision was easy (based on the real use case for raw-string literals).

Answer 5

Even with raw strings, \" causes the " not to be interpreted as the end of the string (though the backslash gets into your string), so r"foo\"bar" would be a legal string. This is convenient enough when writing regex but not great for writing paths.

This is not a big deal as most of the time you should be using os.path and other modules to deal with your paths.