Python用反斜杠替换正斜杠

Question

I have

foo = '/DIR/abc'

and I want to convert it to

bar = '\\MYDIR\data\abc'

So, here's what I do in Python:

>>> foo = '/DIR/abc'
>>> bar = foo.replace(r'/DIR/',r'\\MYDIR\data\')
  File "<stdin>", line 1
    bar = foo.replace(r'/DIR/',r'\\MYDIR\data\')
                                                 ^
SyntaxError: EOL while scanning string literal

If, however, I try to escape the last backslash by entering instead bar = foo.replace(r'/DIR/',r'\\\\MYDIR\\data\\\\') , then I get this monstrosity:

>>> bar2
'\\\\MYDIR\\data\\\\abc'

Help! This is driving me insane.

Answer 1

第二个参数应该是一个字符串，而不是一个正则表达式模式：

foo.replace(r'/DIR/', '\\\\MYDIR\\data\\')

Answer 2

The reason you are encountering this is because of the behavior of the r"" syntax, Taking some explanation from the Python Documentation

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).

So you will need to use a normal escaped string for the last argument.

>>> foo = "/DIR/abc"
>>> print foo.replace(r"/DIR/", "\\\\MYDIR\\data\\")
\\MYDIR\data\abc

Answer 3

我只是在/前面放了一个r来改变正斜杠。

inv_num = line.replace(r'/', '-')

Answer 4

Two problems:

1. A raw literal simply cannot end with a single backslash because it is interpreted as escaping the quote character. Therefore, use a regular (non-raw) literal with escapes: '\\\\\\\\MYDIR\\\\data\\\\' .
2. When displayed (using the repr style), strings will appear with escapes. Therefore, '\\\\\\\\' only has two actual backslashes. So, '\\\\\\\\MYDIR\\\\data\\\\\\\\abc' is really \\\\MYDIR\\data\\\\abc .