From: Robert Klemme <shortcutter@...>
Date: 2009-12-10T23:36:31+09:00
Subject: Re: human-readable listing of array elements

2009/12/10 Aldric Giacomoni <aldric@trevoke.net>:
> This took me less than a minute to write, but I don't know if it's as
> elegant as it could be. Are there more "Ruby-like ways(tm)" to write
> this?
>
> def stringify array
>  return array[0] if array.size == 1
>  string = ""
>  array.each_with_index do |element, index|
>    case index
>      when array.size - 1 # last item
>        string += " and #{element}"
>      when 0
>        string += "#{element}"
>      else
>        string += ", #{element}"
>    end
>  end
>  string
> end

By using String#<< your code will become more efficient because you do
not create new String objects all the time.

For the fun of it here are two other solutions:

irb(main):026:0> def stringify array
irb(main):027:1>   lead = array.slice 0...-1
irb(main):028:1>   lead.empty? ? array.last.to_s : [lead.join(", "),
array.last].join(" and ")
irb(main):029:1> end
=> nil
irb(main):031:0> stringify []
=> ""
irb(main):032:0> stringify %w{foo}
=> "foo"
irb(main):033:0> stringify %w{foo bar}
=> "foo and bar"
irb(main):034:0> stringify %w{foo bar baz}
=> "foo, bar and baz"


irb(main):039:0> def stringify array
irb(main):040:1>   tail = array.slice -2..-1
irb(main):041:1>   tail ? (array.slice(0...-2) << tail.join(" and
")).join(", ") : array.first.to_s
irb(main):042:1> end

irb(main):048:0> stringify []
=> ""
irb(main):045:0> stringify %w{foo}
=> "foo"
irb(main):046:0> stringify %w{foo bar}
=> "foo and bar"
irb(main):047:0> stringify %w{foo bar baz}
=> "foo, bar and baz"

Note, I don't claim that this is necessarily more rubyish. :-)

Kind regards

robert


-- 
remember.guy do |as, often| as.you_can - without end
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