From: Ross Bamford <rosco@...>
Date: 2005-12-22T06:07:49+09:00
Subject: Re: move to front of array

On Wed, 21 Dec 2005 20:08:34 -0000, Payton Swick <payton@foolord.com>  
wrote:

> Hi,
>
> I have an array of Strings, and I'd like to find one of the items by  
> Regexp, then move that item to the front of the array, eg:
>
> array = %w(a B c d Cool e f G)
> array.unshift(array.slice!(array.index(array.find { |i| i =~ /cool/i  
> }))) if array.find { |i| i =~ /cool/i }
>
> Better/cleaner/shorter ways to do it?

Not sure about better or cleaner, but here's a couple of ideas:

Without error checking:

	(ary - [t = ary.detect { |$_| ~/cool/i }]).unshift(t)

If you know there's only one of each element to start with, you could do:

	(ary.unshift(ary.detect { |$_| ~/cool/i })).uniq

still without error checking, or:

	ary.unshift(ti).uniq if ti = ary.detect { |$_| ~/cool/i }

To ensure you don't get a nil at the start, or

	ary.unshift(*ti).uniq if ti = ary.grep(/cool/i)

to ensure you don't get flamed for using $_ ;)

Of course, if you have dupes to start with this won't work.

***
DISCLAIMER
***
I am not advocating the default input space, I don't think you should use  
$_, it's only a few extra characters to do it the 'proper way', I just  
wanted to go for brevity here.
***

:)

-- 
Ross Bamford - rosco@roscopeco.remove.co.uk