Class: Bmg::Summarizer::Positional

Inherits:
Bmg::Summarizer show all
Defined in:
lib/bmg/summarizer/positional.rb

Overview

See First and Last

Direct Known Subclasses

First, Last

Instance Attribute Summary collapse

Attributes inherited from Bmg::Summarizer

#functor, #options

Instance Method Summary collapse

Methods inherited from Bmg::Summarizer

avg, by_proc, collect, concat, count, distinct, distinct_count, first, last, max, median, median_cont, median_disc, min, multiple, percentile, percentile_cont, percentile_disc, stddev, sum, summarization, #summarize, #to_summarizer_name, value_by, variance

Constructor Details

#initialize(*args, &block) ⇒ Positional

Returns a new instance of Positional.

Raises:

  • (ArgumentError) 


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# File 'lib/bmg/summarizer/positional.rb', line 6

def initialize(*args, &block)
  super
  raise ArgumentError, "Missing order" unless options[:order]
  @ordering = Ordering.new(options[:order])
end

Instance Attribute Details

#ordering ⇒ Object (readonly)

Returns the value of attribute ordering.



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# File 'lib/bmg/summarizer/positional.rb', line 11

def ordering
  @ordering
end

Instance Method Details

#finalize(memo) ⇒ Object 



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# File 'lib/bmg/summarizer/positional.rb', line 26

def finalize(memo)
  return nil if memo.nil?
  extract_value(memo)
end

#happens(memo, tuple) ⇒ Object 



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# File 'lib/bmg/summarizer/positional.rb', line 17

def happens(memo, tuple)
  if memo.nil?
    tuple
  else
    c = ordering.call(memo, tuple)
    c <= 0 ? choose(memo, tuple) : choose(tuple, memo)
  end
end

#least ⇒ Object 



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# File 'lib/bmg/summarizer/positional.rb', line 13

def least
  nil
end