From: Tobias Reif <tobiasreif@...>
Date: 2001-12-01T03:35:56+09:00
Subject: [ruby-talk:27104] Re: Help: factored sorting

Bil Kleb wrote:

> 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


sorry, there was trash included...

-----
main_array = ["zed66","alfred39","x1","x3","x2","f5","f2","g7","g9"]

# sort by first letter

main_array.sort!


# group by first letter

group_array          = [[]]
current_group_index  = 0

main_array.each_with_index do |element,index|
   if index == 0
     group_array[0].push element
   elsif element[0].chr == main_array[index-1][0].chr
     group_array[current_group_index].push element
   else
     group_array.push [element]
     current_group_index += 1
   end
end


# sort each group by number

result = group_array.map do |group|
  group.sort do |a,b|
     a.scan(/\d+/).to_s.to_i <=> b.scan(/\d+/).to_s.to_i
   end
end

p result
# -> [["alfred39"], ["f2", "f5"], ["g7", "g9"], ["x1", "x2", "x3"], 
["zed66"]]

-----
Tobi



-- 
Tobias Reif
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