Class: GroupedSet

Inherits:
Array
  • Object
show all
Defined in:
lib/reporting/grouped_set.rb

Overview

Represents an array of Objects which can be grouped according to grouping keys or a grouping block, which returns the hash used for grouping

The objects must support the ‘+’ operation which is used to implode sets of objects with the same grouping hash.

Instance Method Summary collapse

Instance Method Details

#collapse ⇒ Object

Collapse the collection to a single entry



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# File 'lib/reporting/grouped_set.rb', line 44

def collapse
  regroup.first
end

#regroup(*keys, &block) ⇒ Object

Bang method for the regrouping of the data The method takes either a set of keys or a block as grouping criterion

If keys are set the grouping hash is built by calling object.send(key).to_s and concatening for all keys. (e.g. if Object supports the method date the grouping by date is calculated by calling regroup!(:date)

If a block is passed, it is called for every entry and it’s result is taken as grouping hash. (e.g. regroup! { |entry| entry.date } for grouping by date

Objects with identical grouping hash are collapsed by calling the ‘+’ operator on them.

ATTENTION: This method won’t recognize senseless grouping (e.g. calling regroup! { |entry| entry.date.month } followed by regroup! { |entry| entry.date } )



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# File 'lib/reporting/grouped_set.rb', line 32

def regroup(*keys, &block)
  # handle block
  return regroup_by_proc(block) if block_given?

  # handle keys
  block = Proc.new do |entry|
    keys.inject([]) { |memo, column| memo.push entry.send(column.to_sym).to_s }.join('-')
  end
  regroup_by_proc(block)
end