ruby - Ruby 中 gsub 的奇怪行为

Question

puts 'the\t\'arget'.gsub("'", "\\'")

产生以下输出:

the\targetarget

为什么？

Answer 1

gsub 替换中的 \\' 实际上是一个反向引用，即将 ' 字符替换为 ' 字符之后的所有内容在原始字符串中，即 arget。

这是来自 ruby docs on String#gsub 的引述:

If replacement is a String it will be substituted for the matched text. It may contain back-references to the pattern’s capture groups of the form \\d, where d is a group number, or \\k, where n is a group name. If it is a double-quoted string, both back-references must be preceded by an additional backslash. However, within replacement the special match variables, such as &$, will not refer to the current match.