Substituting single quotes in strings

Rails
#1

Hi

I want to substitute single quotes in a string but fails unless
resorting to overkill (imho) techniques like blocks:

s = “ab’cd”
=> “ab’cd”

s.sub("’") {|s| %q{’} }
=> “ab\'cd”

As seen this method works but why can’t I do something like

a.sub("’", %q{’})
=> “aaabbbbbb”

when

a.sub("’", %q{h})
=> “aaahbbb”

works?

Can someone shed some light on this? Thanks in advance.

Regards

Erik

#2

On 16 Dec 2008, at 15:01, Erik L. wrote:

s.sub("’","\\’")

You need four backslashes because:

  • backslashes have to be escaped in a string literal
  • in the case of a sub/gsub subsitution, a backslash has special
    meaning (because you can do stuff like s.sub(/(’)/, “x\1x”) #=>
    “abx’xcd”

Fred

#3

Thanks

I did not think about the potential back reference for regexps. Good
catch.

Regards

Erik