From: Robert Klemme <bob.news@...>
Date: 2006-01-04T22:47:58+09:00
Subject: Re: Newbie question about nested sort

Kroeger, Simon (ext) wrote:
>> From: Robert Klemme [mailto:bob.news@gmx.net]
>>
>> Grehom wrote:
>>> what am I doing wrong?  I wanted to sort primarily on count (second
>>> position in array), then sub-sort alphabetically (first position in
>>> array)
>>>
>>> char_freq = [["c", 2],["b", 5],["a", 2]]
>>> sorted_freq = char_freq.sort {|a, b| b[1]<=>a[1] || a[0]<=>b[0] }
>>> sorted_freq.each do |d|
>>>    print d[0]*d[1]
>>> end
>>>
>>> [...]
>>
>> Generally you need to do conditional evaluation based on higher prio
>> results.  Using "||" or "or" won't help here (dunno what Perl
>> does here).
>>
>> You want something like
>> [...]
>
> hmmm, I don't think he realy *want's* this.
>
> Please don't scare our new perl friends away... :)

:-)))

> there is a simple solution to that:
>
> char_freq = [["c", 2],["b", 5],["a", 2]]
> sorted_freq = char_freq.sort {|a, b| (b[1]<=>a[1]).nonzero? ||
> a[0]<=>b[0] }
> sorted_freq.each do |d|
>    print d[0]*d[1]
> end

I didn't think of using #nonzero? - this clearly resembles the perl
solution most.  Although I'd say that I'd probably prefer the sort_by
approach with negated values...

Kind regards

    robert