如何在Ruby中安全可逆地转义字符串引号？

Question

What is the Ruby equivalent of Python string's encode('string_escape') and decode functions ?

In Python, I can do the following:

>>> s="this isn't a \"very\" good example!"
>>> print s
this isn't a "very" good example!
>>> s
'this isn\'t a "very" good example!'
>>> e=s.encode('string_escape')
>>> print e
this isn\'t a "very" good example!
>>> e
'this isn\\\'t a "very" good example!'
>>> d=e.decode('string_escape')
>>> print d
this isn't a "very" good example!
>>> d
'this isn\'t a "very" good example!'

How to do the equivalent in Ruby?

Answer 1

好吧，你可以这样做：

'string"and"something'.gsub '"', '\"'

Answer 2

Probably inspect

irb(main):001:0> s="this isn't a \"very\" good example!"
=> "this isn't a \"very\" good example!"
irb(main):002:0> puts s
this isn't a "very" good example!
=> nil
irb(main):003:0> puts s.inspect
"this isn't a \"very\" good example!"

note that decoding is much trickier, as inspect also escapes anything not valid in utf-8 files (like binary), so if you know that you will never have anything aside from a limited subset, use gsub, however, the only real way to turn it back into a string is parsing it, either from your own parser or eval :

irb(main):001:0> s = "\" hello\xff I have\n\r\t\v lots of escapes!'"
=> "\" hello\xFF I have\n\r\t\v lots of escapes!'"
irb(main):002:0> puts s
" hello� I have

         lots of escapes!'
=> nil
irb(main):003:0> puts s.inspect
"\" hello\xFF I have\n\r\t\v lots of escapes!'"
=> nil
irb(main):004:0> puts eval(s.inspect)
" hello� I have

         lots of escapes!'
=> nil

obviously, if you are not the one doing the inspect , then don't use eval, write your own/find a parser, however its perfectly safe if you are the one calling inspect right before eval and s is guaranteed to be a string ( s.is_a? String )

Answer 3

I don't know if this is relevant but if I wanted to avoid dealing with escaping I just use %q[ ] syntax

s = %q[this isn't a "very" good example!]
puts s
p s

Will give

'this isn't \ a "very" good example!'
"'this isn't \\ a \"very\" good example!'"