From: Robert Klemme <shortcutter@...>
Date: 2011-07-15T20:04:53+09:00
Subject: Re: Elegant selection of closest number?

On Fri, Jul 15, 2011 at 12:52 PM, 7stud -- <bbxx789_05ss@yahoo.com> wrote:
> Philip Rhoades wrote in post #1010919:
>> People,
>
> buckets = [
>  0.1,
>  0.2,
>  0.3,
>  0.4,
>  0.5,
> ]
>
> data = [
>  0.00,
>  0.14,
>  0.19,
>  0.24,
>  0.25,
>  0.41,
>  1.00,
> ]
>
> results = Hash.new {|hash, key| hash[key] = []}
>
> data.each do |num|
>  rounded = num.round(1)
>
>  first = buckets.first
>  last = buckets.last
>
>  if rounded < first
>    results[first] << num
>  elsif rounded > last
>    results[last] << num
>  else
>    results[rounded] << num
>  end
> end
>
> p results
>
> --output:--
> {0.1=>[0.0, 0.14], 0.2=>[0.19, 0.24], 0.3=>[0.25], 0.4=>[0.41],
> 0.5=>[1.0]}

buckets and data as above

buckets.sort!

result = data.group_by do |x|
  delta = nil
  buck = nil

  buckets.each do |b|
    d = (x - b).abs
    break if delta && d > delta
    delta = d
    buck = b
  end

  buck
end

Kind regards

robert


-- 
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