Python - Raw String Literals

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旧巷少年郎
旧巷少年郎 2021-01-18 02:43

I don\'t understand how raw string literals work. I know that when using r it ignores all specials, like when doing \\n it treats it as \\n and not

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  •  广开言路
    2021-01-18 03:36

    The only way to put in a single quote into a string started with a single quote is to escape it. Thus, both raw and regular string literals will allow escaping of quote characters when you have an unescaped backslash followed by a quote character. Because of the requirement that there must be a way to express single (or double) quotes inside string literals that begin with single (or double) quotes, the string literal '\' is not legal, whether you use a raw or regular string literal.

    To get any arbitrary string with an odd number of literal backslashes, I believe the best way is to use regular string literals. This is because trying to use r'\\' will work, but it will give you a string with two backslashes instead of one:

    >>> '\\' # A single literal backslash.
    '\\'
    >>> len('\\')
    1
    >>> r'\\' # Two literal backslashes, 2 is even so this is doable with raw.
    '\\\\'
    >>> len(r'\\')
    2
    >>> '\\'*3 # Three literal backslashes, only doable with ordinary literals.
    '\\\\\\'
    >>> len('\\'*3)
    3
    

    This answer is only meant to complement the other one.

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