The r in r-strings means raw strings. String literals may optionally be prefixed with a letter 'r' or 'R'; such strings are called raw strings and use different rules for interpreting backslash escape sequences.
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, the string literal r"n" consists of two characters −
String quotes can be escaped with a backslash, but the backslash remains in the string; for example, r""" is a valid string literal consisting of two characters −
The r"" is not a valid string literal. Specifically, a raw string cannot end in a single backslash. A single backslash followed by a newline is interpreted as those two characters as part of the string, not as a line continuation.
For Windows pathnames, the Windows system calls accept forward slashes too −
f = open("/mydir/demo.txt")
Pathname for a DOS command −
dir = r"thisismydosdir" "" dir = r"thisismydosdir "[:-1] dir = "thisismydosdir"
