[ruby-talk:11480] Re: Sorting

"Wilka" <[e-mail]> writes:

> Does Ruby already have an compare method that takes into account numbers
> inside a string? i.e.
> 
> strings = Array.new
> strings.push "Name 300"
> strings.push "Name 1"
> strings.push "Name 10"
> strings.push "Name 2"
> 
> strings.sort do |a, b|
>      # something to put here to sort like a human would
> end

Here are a couple of ways. The second may or may not be more
efficient, as it only does the pattern match and to_i once for each
string in the array.

     strings = [ "Name 300", "Name 1", "Name 10", "Name 2" ]

     # an inefficient way (if there are large numbers of strings)

     digits = /\d+$/

     res = strings.sort { |a, b|  digits.match(a)[0].to_i <=> digits.match(b)[0].to_i}

     # a more efficient way (perhaps)

     res = strings.
         collect {|e|    [ digits.match(e)[0].to_i, e ] }.
         sort    {|a, b| a[0] <=> b[0] }.
         collect {|e|    e[1]}


Regards


Dave