windows中关于末尾"\"换行符的疑问

woodcube

环境：win7 + eclipse + python2.6.4 + pydev

有如下一条赋值语句，运行时出问题了，如下：
    target_dir = r'G:\eclipse_workspace\backup\test\path3\'
                                                          ^
SyntaxError: EOL while scanning string literal
上面的'^'指向的是最后一个单引号
怀疑解释器将最后一个'\'当成了换行了，所以最后的单引号就成了非法字符了。
将字符串首的r去掉也不行，采用下面的方法解决了：
target_dir = r'G:\eclipse_workspace\backup\test\path3\\'

实在不解，r没起作用，无论有没有加都一样，而且为什么前面的'\'符号没有被当做换行符，偏偏最后一个'\'就成了换行符了，这个符号后面明明还有一个单引号的。

求知道的人给解释一下，谢谢。

windwiny

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). Note also that a single backslash followed by a newline is interpreted as those two characters as part of the string, not as a line continuation.

woodcube

谢谢，理解了

icyomik

\ 不是换行，是转义。