From: Ammar Ali <ammarabuali@...>
Date: 2012-04-01T04:53:08+09:00
Subject: Re: regexp replace every other one

On Sat, Mar 31, 2012 at 10:17 PM, gabe gabriellini <lists@ruby-forum.com> wrote:
> puts "Mike Lan move the string abc def".gsub(/(\A|\s)(.{3})($|\s)/,"
> new_value ")
>
> it only replaces two same as the next one only replaces every other one
> what a im missing??

The ending pattern ($|\s) is consuming what would be matched by the
leading pattern (\A|\s) every other match. Making the first part
optional will work:

  /(\A|\s)?(.{3})($|\s)/

If you know the pattern of what you trying to match between the
spaces, for example alphabet only, use a more explicit pattern instead
of .{3}. That way you wouldn't have to deal with the spaces, only what
you want to replace.

>> "abc def ghi jkl mno".gsub(/[a-z]{3}/, "123")
=> "123 123 123 123 123"

Regards,
Ammar