如何将单个反斜杠字符添加到 Ruby 中的字符串? [英] How to add a single backslash character to a string in Ruby?

问题描述

我想在儿童世界"字符串中的撇号前插入反斜杠.有没有简单的方法?

I want to insert backslash before apostrophe in "children's world" string. Is there a easy way to do it?

irb(main):035:0> s = "children's world"
=> "children's world"
irb(main):036:0> s.gsub('\'', '\\\'')
=> "childrens worlds world"

推荐答案

from ruby-doc.org 关于 gsub 的替换模式:

from ruby-doc.org about the replacement pattern for gsub:

序列\1、\2 等可用于插入匹配中的连续组

the sequences \1, \2, and so on may be used to interpolate successive groups in the match

这包括序列 \'，意思是我匹配的所有内容".

This includes the sequence \', which means "everything following what I matched".

无论是 "\\'" 还是 '\\\'' 都会产生 \'(记住 \ 必须在双 和 单引号字符串中转义，并且 ' 必须在单引号字符串中转义，因此在这种情况下使用单引号实际上使事情更冗长).例如:

Either "\\'" or '\\\'' will both produce \' (remember that \ has to be escaped in both double and single quoted strings, and that ' has to be escaped in single-quoted strings, so using single-quotes in this case actually makes things more verbose). E.g.:

puts "before*after".gsub("*", "\\'")
"beforeafterafter"

puts "before*after".gsub("*", '\\\'')
"beforeafterafter"

你想让 gsub 看到的实际上是 \\'，它可以由 "\\\\'" 产生和 '\\\\''.所以:

What you want gsub to see then is actually \\', which can be produced by both "\\\\'" and '\\\\\''. So:

puts s.gsub("'", "\\\\'")
children\'s world

puts s.gsub("'", '\\\\\'')
children\'s world

或者如果你必须用 \ 做很多事情，你可以利用这样一个事实，当你使用 /.../ (或 %r{...}) 你不必双重转义反斜杠:

or if you have to do a lot with \ you could take advantage of the fact that when you use /.../ (or %r{...}) you don't have to double-escape the backslashes:

puts s.gsub("'", /\\'/.source)
children\'s world

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