Class: Wukong::Processor::Sample

Inherits:

Filter

• Object
• Hanuman::Stage
• Wukong::Processor
• Filter
• Wukong::Processor::Sample

Defined in:

lib/wukong/widget/filters.rb

Overview

A widget which samples a certain fraction of input records.

Examples:

Sampling records on the command line

$ cat input
1
2
3
4
$ cat input | wu-local sample --fraction=0.5
1
3

Sampling records in a dataflow

Wukong.dataflow(:uses_sample) do
  ... | sample(fraction: 0.5) ...
end

See Also:

• Filter
• Limit

Constant Summary

Constants inherited from Wukong::Processor

SerializerError

Instance Attribute Summary

Attributes included from Hanuman::StageInstanceMethods

#graph

Instance Method Summary

• #select?(record) ⇒ true, false

  Selects a record randomly, with a probability given the the fraction for this widget.

Methods inherited from Filter

#process, #reject?

Methods inherited from Wukong::Processor

configure, description, #finalize, #perform_action, #process, #receive_action, #setup, #stop

Methods included from Logging

included

Methods inherited from Hanuman::Stage

#clone

Methods included from Hanuman::StageClassMethods

#builder, #label, #register, #set_builder

Methods included from Hanuman::StageInstanceMethods

#add_link, #linkable_name, #root

Instance Method Details

#select?(record) ⇒ true, false

Selects a record randomly, with a probability given the the fraction for this widget.

Parameters:

• record (Object)

Returns:

• (true, false)

# File 'lib/wukong/widget/filters.rb', line 313

def select?(record)
  rand() < fraction
end