gsub 中的反斜杠（转义和反向引用）
考虑以下代码片段：
puts 'hello'.gsub(/.+/, '\0 \\0 \\\0 \\\\0')
此打印（如 ideone.com 上所示）：
hello hello \0 \0
这非常令人惊讶，因为我期望看到类似这样的内容：
hello \0 \hello \\0
我的论点是 \ 是转义字符，因此您编写 \\ 来获得文字反斜杠，因此 \\0 是一个反斜杠 \ 后跟 0 等。显然这不是 gsub 的解释方式，所以有人可以解释一下这是怎么回事？
我需要做什么才能得到上面我想要的替代品？
Consider the following snippet:
puts 'hello'.gsub(/.+/, '\0 \\0 \\\0 \\\\0')
This prints (as seen on ideone.com):
hello hello \0 \0
This was very surprising, because I'd expect to see something like this instead:
hello \0 \hello \\0
My argument is that \ is an escape character, so you write \\ to get a literal backslash, thus \\0 is a literal backslash \ followed by 0, etc. Obviously this is not how gsub is interpreting it, so can someone explain what's going on?
And what do I have to do to get the replacement I want above?
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使用单引号而不是双引号时，转义受到限制：
"\0"是空字符（在 C 中用于确定字符串的结尾），其中'\0 '是"\\0"，因此'hello'.gsub(/.+/, '\0')和'hello '.gsub(/.+/, "\\0")返回"hello"，但'hello'.gsub(/.+/, "\0" )返回“\000”。现在'hello'.gsub(/.+/, '\\0')返回'hello'是 ruby 试图处理程序员不保留 single 和 single 之间的差异的问题记住双引号。事实上，这与gsub无关：'\0' == "\\0"和'\\0' == "\\ 0”。遵循这个逻辑，无论您怎么想，这就是 ruby 如何看待其他字符串：'\\\0'和'\\\\0'相等"\\\\0"，（打印时）为您提供\\0。由于 gsub 使用\x来插入匹配号 x，因此您需要一种方法来转义\x，即\\x，或者在其字符串表示："\\\\x"。因此这条线
确实导致
Escaping is limited when using single quotes rather then double quotes:
"\0"is the null-character (used i.e. in C to determine the end of a string), where as'\0'is"\\0", therefore both'hello'.gsub(/.+/, '\0')and'hello'.gsub(/.+/, "\\0")return"hello", but'hello'.gsub(/.+/, "\0")returns"\000". Now'hello'.gsub(/.+/, '\\0')returning'hello'is ruby trying to deal with programmers not keeping the difference between single and double quotes in mind. In fact, this has nothing to do withgsub:'\0' == "\\0"and'\\0' == "\\0". Following this logic, whatever you might think of it, this is how ruby sees the other strings: both'\\\0'and'\\\\0'equal"\\\\0", which (when printed) gives you\\0. As gsub uses\xfor inserting match number x, you need a way to escape\x, which is\\x, or in its string representation:"\\\\x".Therefore the line
indeed results in