From: Rahul Kumar <sentinel1879@...>
Date: 2010-10-13T21:53:53+09:00
Subject: Re: sort_by: multiple fields with reverse sort

When i sat down to code, i realized that i could not just put the 
sort_keys list to sort_by, i would have to unroll the sort_keys array. 
So, i might as well use sort. This seems to work in the small case i 
have. Could someone comment on this, and suggest cleaner better way to 
do. Thanks.

b=[ ["radio", 30, 5], ["radio", 20, 5], ["archie", 20, 5], ["newton", 
10, 3] ]
sort_keys=[1,0]
rev_flag = [true, false]

c=b.sort{|x,y|
  res = 0
  sort_keys.each_with_index { |e,i|
    if rev_flag[i]
      res = y[e] <=> x[e]
    else
      res = x[e] <=> y[e]
    end
    break if res != 0
  }
  res
}
c

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