Class: Streamer::Functors::Group

Inherits:
Functor
  • Object
show all
Defined in:
lib/streamer/functors/group.rb

Overview

Group groups a list by a property and a function

Instance Attribute Summary

Attributes inherited from Functor

#options, #payload

Instance Method Summary collapse

Methods inherited from Functor

#class_name, #initialize, #type_name

Constructor Details

This class inherits a constructor from Streamer::Functors::Functor

Instance Method Details

#accumulate(list, group_key, operand_key, operator) ⇒ Object 



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# File 'lib/streamer/functors/group.rb', line 16

def accumulate(list, group_key, operand_key, operator)
  list.each_with_object({}) do |item, val|
    val[item[group_key]] =
      (val[item[group_key]] || 0.0).send(
        operator,
        (item[operand_key].to_f || 0)
      )
  end
end

#call ⇒ Object 



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# File 'lib/streamer/functors/group.rb', line 5

def call
  group
end

#group ⇒ Object 



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# File 'lib/streamer/functors/group.rb', line 9

def group
  group_key = options.fetch(:by)
  operand_key = options.fetch(:operand)
  operator = options.fetch(:operator).to_sym
  accumulate(list, group_key, operand_key, operator)
end