Module: Mongoid::Contextual::Aggregable::Memory

Includes:
FieldReadable
Included in:
Memory
Defined in:
lib/mongoid/contextual/aggregable/memory.rb

Overview

Contains behavior for aggregating values in memory.

Instance Method Summary collapse

Instance Method Details

#aggregates(field) ⇒ Hash

Get all the aggregate values for the provided field. Provided for interface consistency with Aggregable::Mongo.

Parameters:

  • field (String | Symbol) —

    The field name.

Returns:

  • (Hash) —

    A Hash containing the aggregate values. If no documents are present, then returned Hash will have count, sum of 0 and max, min, avg of nil.



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# File 'lib/mongoid/contextual/aggregable/memory.rb', line 20

def aggregates(field)
  %w[count sum avg min max].each_with_object({}) do |method, hash|
    hash[method] = send(method, field)
  end
end

#avg(field) ⇒ Numeric

Get the average value of the provided field.

Examples:

Get the average of a single field.

aggregable.avg(:likes)

Parameters:

  • field (Symbol) —

    The field to average.

Returns:

  • (Numeric) —

    The average.



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# File 'lib/mongoid/contextual/aggregable/memory.rb', line 34

def avg(field)
  total = count { |doc| !read_field_value(doc, field).nil? }
  return nil unless total > 0

  total = total.to_f if total.is_a?(Integer)
  sum(field) / total
end

#max(field = nil) ⇒ Numeric | Document

Get the max value of the provided field. If provided a block, will return the Document with the greatest value for the field, in accordance with Ruby's enumerable API.

Examples:

Get the max of a single field.

aggregable.max(:likes)

Get the document with the max value.

aggregable.max do |a, b|
  a.likes <=> b.likes
end

Parameters:

  • field (Symbol) (defaults to: nil) —

    The field to max.

Returns:

  • (Numeric | Document) —

    The max value or document with the max value.



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# File 'lib/mongoid/contextual/aggregable/memory.rb', line 58

def max(field = nil)
  return super() if block_given?

  aggregate_by(field, :max)
end

#min(field = nil) ⇒ Numeric | Document

Get the min value of the provided field. If provided a block, will return the Document with the smallest value for the field, in accordance with Ruby's enumerable API.

Examples:

Get the min of a single field.

aggregable.min(:likes)

Get the document with the min value.

aggregable.min do |a, b|
  a.likes <=> b.likes
end

Parameters:

  • field (Symbol) (defaults to: nil) —

    The field to min.

Returns:

  • (Numeric | Document) —

    The min value or document with the min value.



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# File 'lib/mongoid/contextual/aggregable/memory.rb', line 80

def min(field = nil)
  return super() if block_given?

  aggregate_by(field, :min)
end

#sum(field = nil) ⇒ Numeric

Get the sum value of the provided field. If provided a block, will return the sum in accordance with Ruby's enumerable API.

Examples:

Get the sum of a single field.

aggregable.sum(:likes)

Get the sum for the provided block.

aggregable.sum(&:likes)

Parameters:

  • field (Symbol | Numeric) (defaults to: nil) —

    The field to sum, or the initial value of the sum when a block is given.

Returns:

  • (Numeric) —

    The sum value.



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# File 'lib/mongoid/contextual/aggregable/memory.rb', line 99

def sum(field = nil)
  return super(field || 0) if block_given?

  aggregate_by(field, :sum) || 0
end