Replacing ' with \' using gsub

[Jani Soila]

I tried to replace "'" characters with "\'" strings using gsub. What
happened instead was something completely different. Am I missing
something here?
(in irb)
irb(main):001:0> s = "a'b'"
=> "a'b'"
Unexpected result
irb(main):002:0> s.gsub(/'/, "\\'")
=> "ab'b"
Also with this
irb(main):003:0> s.gsub(/'/, '\\\'')
=> "ab'b"
However this works
irb(main):004:0> s.gsub(/'/, "\\x'")
=> "a\\x'b\\x'"

Thank you for your help!
-js

 

[Jan Svitok]

Seems to me like a bug in the regex code.
using ruby 1.8.4 (2005-12-24) [i386-mswin32]

J.

 

[Phrogz]

Seems to me like a bug in the regex code.
using ruby 1.8.4 (2005-12-24) [i386-mswin32]

But it isn't. You need more backslashes.

See "Explanation for the multitude of backslashes " at
http://wiki.rubygarden.org/Ruby/page/show/RegexpCookbook
or search the list archives, as this comes up frequently by newcomers
(including myself, when I was young .

 

[Morton Goldberg]

irb(main):001:0> s = "a'b'"
=> "a'b'"
irb(main):002:0> s.gsub(/'/, "\\\'")
=> "ab'b"
irb(main):003:0> s.gsub(/'/, "\\\\\'")
=> "a\\'b\\'"

Regards, Morton

 

[ts]

J> irb(main):001:0> s = "a'b'"
J> => "a'b'"
J> Unexpected result
J> irb(main):002:0> s.gsub(/'/, "\\'")
J> => "ab'b"

"\\'" is the same than $', i.e. MatchData#post_match. For example

irb(main):001:0> s = "a'b'"
=> "a'b'"
irb(main):002:0> s.match(/'/).post_match
=> "b'"
irb(main):003:0>

ruby replace the first <'> with <b'>
the second <'> with <> (there is nothing after the last ')


Guy Decoux

 

[Logan Capaldo]

J> irb(main):001:0> s = "a'b'"
J> => "a'b'"
J> Unexpected result
J> irb(main):002:0> s.gsub(/'/, "\\'")
J> => "ab'b"

"\\'" is the same than $', i.e. MatchData#post_match. For example

irb(main):001:0> s = "a'b'"
=> "a'b'"
irb(main):002:0> s.match(/'/).post_match
=> "b'"
irb(main):003:0>

ruby replace the first <'> with <b'>
the second <'> with <> (there is nothing after the
last ')


Guy Decoux

What he said.

Also if you don't want to drive yourself crazy with fifteen billion
backslahes:

str.gsub(/'/) { %q{\'} }