From: "J. Cooper" <nefigah@...>
Date: 2008-02-23T02:37:49+09:00
Subject: Re: gsub("\\", "\\\\") seems unintuitive

John Woods wrote:
> The following confusing behavior is noted in the pickaxe book (2nd ed)
> on page 75:
> 
>    # I would expect two backslashes in the result
>    irb> puts "\\".gsub("\\","\\\\")
>    \
> 
>    # I would expect four backslashes in the result
>    irb> puts "\\".gsub("\\","\\\\\\\\")
>    \\
> 
> I can certainly work around it, but it seems unintuitive. Is there a
> reason why gsub behaves this way? Just curious...

It's not a gsub thing, per se--it's a string thing. Backslashes are used 
in strings to escape special characters. One such character is a " mark. 
If you want to write a " mark in the middle of a string, you have to 
escape it with a backslash:
"They call me \"Mellow Yellow\" etc."

If you didn't, then the " would signify the end of the string!
Similarly, in the example you listed, if you just did:
"\"
then you end up with a string that ISN'T ended! Because you escaped the 
next ". So, if you want a literal backslash, you have to escape the 
backslash too: "\\"

It just looks confusing because you are escaping the escape character :)


-- 
Posted via http://www.ruby-forum.com/.