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So I think this is weird:

"x'y".gsub("'", "\\'")
=> "xyy"

The variant, 

'x"y'.gsub('"', "\'")
=> "x'y"

Works just fine.

Either it's a bug (unlikely) or it's something with how Ruby handles backreferences that I don't understand. Can anyone explain what happens in the first case?

Confusion
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1 Answers1

1

\' means $' which is everything after the match.
(or)
\' in a gsub replacement means "part of the string after the match."

Escape the \ again and it works,

"x'y".gsub("'", "\\\\'")

you can also use %q delimiters here,

"x'y".gsub("'", %q(\\\'))  

//(IRB uses \\ to make an escape-\ visible)

Referred from Gsub wierd behaviour

Community
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Sravan
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  • Do you know if this is documented anywhere? The documentation for [sub](http://ruby-doc.org/core-2.3.1/String.html#method-i-gsub) even says `[..] but is actually not a pattern capture group e.g. "\'", then it will have to be preceded by two backslashes like so "\\'"` – Confusion Jul 28 '16 at 13:29
  • Me too didn't get the correct documentation of it any where, but as we need to escape the escape character and single quote so shld use 4 back slashes there. – Sravan Jul 28 '16 at 13:44