在python中r'\'不是一个有效的字符串值吗？

Question

Possible Duplicate:
why can’t I end a raw string with a \

既然r'\\'等价于'\\\\'，那么{}为什么不等价于{}？在

我在我的Python3.2上看到的是

print(r'\')
  File "<stdin>", line 1
    print(r'\')
              ^
SyntaxError: EOL while scanning string literal

Answer 1

反斜杠不能作为原始字符串中的最后一个字符，除非它是偶数个反斜杠的一部分；它会转义右引号。在

将其与：

>>> r'\ '
'\\ '

从string literal documentation：

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: a backslash and a lowercase 'n'. 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: a backslash and a double quote; r"\" is not a valid string literal (even a raw string cannot end in an odd number of backslashes). Specifically, a raw string cannot end in a single backslash (since the backslash would escape the following quote character).