不接受Python Literal r'\' [英] Python Literal r'\' Not Accepted

问题描述

r'\'不能按预期工作.而不是返回其中包含一个字符(反斜杠)的字符串，而是引发SyntaxError. r"\"也是一样.

r'\' in Python does not work as expected. Instead of returning a string with one character (a backslash) in it, it raises a SyntaxError. r"\" does the same.

如果您具有如下所示的Windows路径列表，那么这将很麻烦:

This is rather cumbersome if you have a list of Windows paths like these:

paths = [ r'\bla\foo\bar',
          r'\bla\foo\bloh',
          r'\buff',
          r'\',
          # ...
        ]

为什么没有接受此文字的充分理由?

Is there a good reason why this literal is not accepted?

推荐答案

我的问题的答案(为什么不允许在原始字符串中将反斜杠用作最后一个字符?")实际上对我来说似乎是这是一个设计决策" ，还有一个值得怀疑的地方.

The answer to my question ("Why is a backslash not allowed as last character in raw strings?") actually to me seems to be "That's a design decision", furthermore a questionable one.

一些答案​​试图说明词法分析器和某些语法突出显示器以这种方式更简单.我不同意(并且我在编写解析器和编译器以及IDE开发方面有一定的背景知识).使用反斜杠没有任何特殊含义的语义来定义原始字符串会更简单. lexer和IDE都将从这种简化中受益.

Some answers tried to reason that the lexer and some syntax highlighters are simpler this way. I don't agree (and I have some background on writing parsers and compiler as well as IDE development). It would be simpler to define raw strings with the semantics that a backslash has no special meaning whatsoever. Both lexer and IDE would benefit from this simplification.

目前的情况也是疣:如果我想要引用在原始字符串中，无论如何我都不能使用它.如果我恰好想要在原始字符串中加一个反斜杠后跟一个引号，则只能使用它.

The current situation also is a wart: In case I want a quote in a raw string, I cannot use this anyway. I only can use it if I happen to want a backslash followed by a quote inside my raw string.

我建议对此进行更改，但是我也看到了破坏现有代码的问题:-/

I would propose to change this, but I also see the problem of breaking existing code :-/

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