Goldmine

Extract a wealth of information from Arrays & Hashes. Think of Goldmine as Enumerable#group_by on steroids.

Uses

• Data mining
• Data transformation
• CSV report generation
• Prep for data visualization
• Fact table creation

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The demo project demonstrates some of Goldmine's uses.

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Quick Start

gem install goldmine

require "goldmine"

list = [1,2,3,4,5,6,7,8,9]
list = Goldmine::ArrayMiner.new(list)
list.pivot { |i| i < 5 }
# result:
{
  true  => [1, 2, 3, 4],
  false => [5, 6, 7, 8, 9]
}

Chained Pivots

list = [1,2,3,4,5,6,7,8,9]
list = Goldmine::ArrayMiner.new(list)
list.pivot { |i| i < 5 }.pivot { |i| i % 2 == 0 }
# result:
{
  [true, false]  => [1, 3],
  [true, true]   => [2, 4],
  [false, false] => [5, 7, 9],
  [false, true]  => [6, 8]
}

Named Pivots

list = [1,2,3,4,5,6,7,8,9]
list = Goldmine::ArrayMiner.new(list)
list.pivot(:less_than_5) { |i| i < 5 }
# result:
{
  { :less_than_5 => true }  => [1, 2, 3, 4],
  { :less_than_5 => false } => [5, 6, 7, 8, 9]
}

Value Pivots

list = [
  { :name => "Sally",   :favorite_colors => [:blue] },
  { :name => "John",    :favorite_colors => [:blue, :green] },
  { :name => "Stephen", :favorite_colors => [:red, :pink, :purple] },
  { :name => "Emily",   :favorite_colors => [:orange, :green] },
  { :name => "Joe",     :favorite_colors => [:red] }
]
list = Goldmine::ArrayMiner.new(list)
list.pivot { |record| record[:favorite_colors] }
# result:
{
  :blue => [
    { :name => "Sally", :favorite_colors => [:blue] },
    { :name => "John",  :favorite_colors => [:blue, :green] }
  ],
  :green => [
    { :name => "John",  :favorite_colors => [:blue, :green] },
    { :name => "Emily", :favorite_colors => [:orange, :green] }
  ],
  :red => [
    { :name => "Stephen", :favorite_colors => [:red, :pink, :purple] },
    { :name => "Joe",     :favorite_colors => [:red] }
  ],
  :pink => [
    { :name => "Stephen", :favorite_colors => [:red, :pink, :purple] }
  ],
  :purple => [
    { :name => "Stephen", :favorite_colors => [:red, :pink, :purple] }
  ],
  :orange => [
    { :name => "Emily", :favorite_colors => [:orange, :green] }
  ]
}

Stacked pivots

list = [
  { :name => "Sally",   :age => 21 },
  { :name => "John",    :age => 28 },
  { :name => "Stephen", :age => 37 },
  { :name => "Emily",   :age => 32 },
  { :name => "Joe",     :age => 18 }
]
list = Goldmine::ArrayMiner.new(list)
mined = list.pivot("Name has an 'e'") do |record|
  !!record[:name].match(/e/i)
end
mined = mined.pivot(">= 21 years old") do |record|
  record[:age] >= 21
end
# result:
{
  { "Name has an 'e'" => false, ">= 21 years old" => true } => [
    { :name => "Sally", :age => 21 },
    { :name => "John",  :age => 28 }
  ],
  { "Name has an 'e'" => true, ">= 21 years old" => true } => [
    { :name => "Stephen", :age => 37 },
    { :name => "Emily",   :age => 32 }
  ],
  { "Name has an 'e'" => true, ">= 21 years old" => false } => [
    { :name => "Joe", :age => 18 }
  ]
}