From: Ralph Mason <ralph.mason@...>
Date: 2001-11-30T14:37:35+09:00
Subject: [ruby-talk:27027] Re: Help: factored sorting

It's just a matter of making the all the items count

so your expression should be something like

def val(x)
    x[0] * 1000 + x.scan(/\d+/).to_s.to_i 
end

a.sort { |a,b| sval(a) <=> sval(b) }

As someone once said, I have not tried this but it should work

Ralph



----- Original Message ----- 
From: "Bil Kleb" <W.L.Kleb@LaRC.NASA.Gov>
Newsgroups: comp.lang.ruby
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>; <undisclosed-recipients:>
Sent: Friday, November 30, 2001 6:16 PM
Subject: [ruby-talk:27026] Help: factored sorting


> I have an array of strings,
> 
> a = ["d3", "d33", "d4", "r16", "r33", "d34", "r34"]
> 
> which I'd like to sort by both the numerical suffix and by
> the alphabetic prefix, i.e., I'd like the result,
> 
>  ["d3", "d4", "d33", "d34", "r16", "r33", "r34"]
> 
> or, even better would be an array of two prefix-keyed
> sub arrays that I could exploit with the assoc method,
> viz,
> 
>  [ ["d", "d3", "d4", "d33", "d34"], ["r", "r16", "r33", "r34"] ]
> 
> A straight lexiconic sort, e.g., a.sort, gives all
> the d's followed by the r's, but does not yield the
> desired numerical ordering because the single and double
> digit integer suffixes, viz,
> 
>  ["d3", "d33", "d34", "d4", "r16", "r33", "r34"] 
> 
> Meanwhile an (inept?) numerical sorting, e.g.,
> 
> a.sort { |a,b| a.scan(/\d+/).to_s.to_i <=> b.scan(/\d+/).to_s.to_i }
> 
> gives the desired numerical sequence, but mixes the d and r prefixes
> together, viz,
> 
>  ["d3", "d4", "r16", "d33", "r33", "d34", "r34"]
> 
> Is there an elegant way to accomplish this type of factored sort
> without resorting to padding the digit suffix or similar convoluted
> mechanics?
> 
> TIA,
> --
> Bil <http://abweb.larc.nasa.gov/~kleb/>
>