From: Jon Garvin <jgarvin.lists@...>
Date: 2009-02-11T03:26:41+09:00
Subject: Re: regex to escape special characters

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Tim Hunter wrote:
> Jon Garvin wrote:
>   
>> I've got the following string...
>>
>> "This is ( a test"
>>
>> And I want to do a regex gsub on it to turn it into...
>>
>> "This is \( a test"
>>
>> In irb, If I start with...
>>
>>  "This is ( a test".gsub(/[\(]/,'\&')        => "This is ( a test"
>>
>> And then progressively added more backslashes, I get the following
>> results, none of which are what I'm looking for.  The second one is,
>> IMO, the one that should work.
>>
>> "This is ( a test".gsub(/[\(]/,'\\&')   => "This is ( a test"
>> "This is ( a test".gsub(/[\(]/,'\\\&')  => "This is \\& a test"
>> "This is ( a test".gsub(/[\(]/,'\\\\&') => "This is \\& a test"
>> "This is ( a test".gsub(/[\(]/,'\\\\\&')=> "This is \\( a test"
>>
>>
>> Am I just having a serious case of the mondays, or is there a bug in how
>> Ruby deals with \ characters when trying to represent an actual single \
>> character?
>>
>> I'm using ruby 1.8.6 (2007-09-24 patchlevel 111) [i486-linux]
>>     
>
> irb shows you the result using p, which escapes special characters in 
> the string it displays. Use puts to see the actual string.
>
> C:\>irb
> irb(main):001:0> x = "This is ( a test"
> => "This is ( a test"
> irb(main):002:0> x.gsub(/\(/, '\\\(')
> => "This is \\( a test"
> irb(main):003:0> y = x.gsub(/\(/, '\\\(')
> => "This is \\( a test"
> irb(main):004:0> puts y
> This is \( a test
> => nil
> irb(main):005:0>
>   
Oh, fer cryin' out loud.  Case of the mondays it is.  Thanks.

-- 

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