Class: Weka::Core::Instances

Inherits:
Object
  • Object
show all
Includes:
Weka::Concerns::Persistent, Weka::Concerns::Serializable
Defined in:
lib/weka/core/instances.rb

Constant Summary collapse

DEFAULT_RELATION_NAME = 
'Instances'.freeze

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Weka::Concerns::Serializable

#serialize

Methods included from Weka::Concerns::Persistent

included

Constructor Details

#initialize(relation_name: DEFAULT_RELATION_NAME, attributes: []) ⇒ Instances

Returns a new instance of Instances.



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# File 'lib/weka/core/instances.rb', line 43

def initialize(relation_name: DEFAULT_RELATION_NAME, attributes: [])
  attribute_list = FastVector.new
  attributes.each { |attribute| attribute_list.add_element(attribute) }

  super(relation_name.to_s, attribute_list, 0)
end

Class Method Details

.from_arff(file) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 20

def from_arff(file)
  Loader.load_arff(file)
end

.from_c45(file) ⇒ Object

Loads instances based on a given *.names file (holding the attribute values) or a given *.data file (holding the attribute values). The respective other file is loaded from the same directory.

See www.cs.washington.edu/dm/vfml/appendixes/c45.htm for more information about the C4.5 file format.



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# File 'lib/weka/core/instances.rb', line 38

def from_c45(file)
  Loader.load_c45(file)
end

.from_csv(file) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 24

def from_csv(file)
  Loader.load_csv(file)
end

.from_json(file) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 28

def from_json(file)
  Loader.load_json(file)
end

Instance Method Details

#add_attributes(&block) ⇒ Object Also known as: with_attributes 



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# File 'lib/weka/core/instances.rb', line 72

def add_attributes(&block)
  instance_eval(&block) if block
  self
end

#add_instance(instance_or_values, weight: 1.0) ⇒ Object

Add new instance

Examples:

Passing Instance

instances.add_instance(instance)

Passing an array of attribute values

attr_values = [attr1_value, attr2_value, attr3_value]
instances.add_instance(attr_values)

Passing a hash of attribute values.

attr_values = { attr1_name: attr1_value, attr2_name: attr2_value }
instances.add_instance(attr_values)

Parameters:

  • instance_or_values (Instance, Array, Hash) —

    the attribute values of the instance to be added. If passing an array, the attribute values must be in the same order as the attributes defined in Instances. If passing a hash, The keys are the names of the attributes and their values are corresponding attributes values.



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# File 'lib/weka/core/instances.rb', line 226

def add_instance(instance_or_values, weight: 1.0)
  instance = instance_from(instance_or_values, weight: weight)
  add(instance)
end

#add_instances(data, weight: 1.0) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 231

def add_instances(data, weight: 1.0)
  data.each { |values| add_instance(values, weight: weight) }
end

#apply_filter(filter) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 255

def apply_filter(filter)
  filter.filter(self)
end

#apply_filters(*filters) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 259

def apply_filters(*filters)
  filters.inject(self) do |filtered_instances, filter|
    filter.filter(filtered_instances)
  end
end

#attribute_names(include_class_attribute: false) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 68

def attribute_names(include_class_attribute: false)
  attributes(include_class_attribute: include_class_attribute).map(&:name)
end

#attributes(include_class_attribute: false) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 59

def attributes(include_class_attribute: false)
  attrs = enumerate_attributes.to_a

  class_available = include_class_attribute && class_attribute_defined?
  attrs.insert(class_index, class_attribute) if class_available

  attrs
end

#class_attribute ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 196

def class_attribute
  classAttribute if class_attribute_defined?
end

#class_attribute=(name) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 182

def class_attribute=(name)
  if name.nil?
    reset_class_attribute
  else
    ensure_attribute_defined!(name)
    setClass(attribute_with_name(name))
  end
end

#class_attribute_defined? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/weka/core/instances.rb', line 204

def class_attribute_defined?
  class_index >= 0
end

#copy ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 50

def copy
  constructor = Instances.java_class.declared_constructor(Instances)
  constructor.new_instance(self).to_java(Instances)
end

#date(name, format: 'yyyy-MM-dd HH:mm', class_attribute: false) ⇒ Object Also known as: add_date_attribute 



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# File 'lib/weka/core/instances.rb', line 176

def date(name, format: 'yyyy-MM-dd HH:mm', class_attribute: false)
  attribute = Attribute.new_date(name, format)
  add_attribute(attribute)
  self.class_attribute = name if class_attribute
end

#each(&block) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 101

def each(&block)
  if block_given?
    enumerate_instances.each(&block)
  else
    enumerate_instances
  end
end

#each_attribute(&block) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 117

def each_attribute(&block)
  if block_given?
    enumerate_attributes.each(&block)
  else
    enumerate_attributes
  end
end

#each_attribute_with_index(&block) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 125

def each_attribute_with_index(&block)
  if block_given?
    enumerate_attributes.each_with_index(&block)
  else
    enumerate_attributes
  end
end

#each_with_index(&block) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 109

def each_with_index(&block)
  if block_given?
    enumerate_instances.each_with_index(&block)
  else
    enumerate_instances
  end
end

#has_attribute_type?(type) ⇒ Boolean

Check if the instances has any attribute of the given type

Examples:

Passing String

instances.has_attribute_type?('string')
instances.has_attribute_type?('String')

Passing Symbol

instances.has_attribute_type?(:String)

Passing Integer

instances.has_attribute_type?(Attribute::STRING)

Parameters:

  • type (String, Symbol, Integer) —

    type of the attribute to check String and Symbol argument are converted to corresponding type defined in Weka::Core::Attribute

Returns:

  • (Boolean) 


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# File 'lib/weka/core/instances.rb', line 96

def has_attribute_type?(type)
  type = map_attribute_type(type) unless type.is_a?(Integer)
  check_for_attribute_type(type)
end

#instance_from(instance_or_values, weight: 1.0) ⇒ Instance

Wrap the attribute values for the instance to be added with

an Instance object, if needed. The Instance object is
assigned with the given weight.

Parameters:

  • instance_or_values (Instance, Array, Hash) —

    either the instance object to be added or the attribute values for it. For the latter case, it accepts an array or a hash.

  • weight (Float) (defaults to: 1.0) —

    the weight for the Instance to be added

Returns:

  • (Instance) —

    the object that contains the given attribute values.



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# File 'lib/weka/core/instances.rb', line 290

def instance_from(instance_or_values, weight: 1.0)
  dataset = string_free_structure

  if instance_or_values.is_a?(Java::WekaCore::Instance)
    instance = instance_or_values
    instance.weight = weight
  else
    data = instance_data(instance_or_values)
    instance = DenseInstance.new(data, weight: weight)
  end

  dataset.add(instance)
  dataset.first
end

#instances ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 55

def instances
  enumerate_instances.to_a
end

#internal_values_of(values) ⇒ Array, Hash

Retrieve the internal floating point values used to represent

the attributes.

Parameters:

  • values (Array, Hash) —

    the attribute values whose floating point representation should be retrieved.

Returns:

  • (Array, Hash) —

    an array of the internal floating point representation if the input is an Array. Hash otherwise.



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# File 'lib/weka/core/instances.rb', line 243

def internal_values_of(values)
  use_hash = values.is_a?(Hash)
  values = attribute_values_from_hash(values) if use_hash

  values = values.map.with_index do |value, index|
    attribute(index).internal_value_of(value)
  end

  values = attribute_values_to_hash(values) if use_hash
  values
end

#merge(*instances) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 265

def merge(*instances)
  instances.inject(self) do |merged_instances, dataset|
    self.class.merge_instances(merged_instances, dataset)
  end
end

#nominal(name, values:, class_attribute: false) ⇒ Object Also known as: add_nominal_attribute 



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# File 'lib/weka/core/instances.rb', line 164

def nominal(name, values:, class_attribute: false)
  attribute = Attribute.new_nominal(name, values)
  add_attribute(attribute)
  self.class_attribute = name if class_attribute
end

#numeric(name, class_attribute: false) ⇒ Object Also known as: add_numeric_attribute 



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# File 'lib/weka/core/instances.rb', line 158

def numeric(name, class_attribute: false)
  attribute = Attribute.new_numeric(name)
  add_attribute(attribute)
  self.class_attribute = name if class_attribute
end

#reset_class_attribute ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 200

def reset_class_attribute
  set_class_index(-1)
end

#string(name, class_attribute: false) ⇒ Object Also known as: add_string_attribute 



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# File 'lib/weka/core/instances.rb', line 170

def string(name, class_attribute: false)
  attribute = Attribute.new_string(name)
  add_attribute(attribute)
  self.class_attribute = name if class_attribute
end

#to_arff(file) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 133

def to_arff(file)
  Saver.save_arff(file: file, instances: self)
end

#to_c45(file) ⇒ Object

Creates a file with the istances’s attribute values and a *.data file with the actual data.

You should choose another file extension than .data (preferably *.names) for the file, else it will just be overwritten with the automatically created *.data file.

See www.cs.washington.edu/dm/vfml/appendixes/c45.htm for more information about the C4.5 file format.



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# File 'lib/weka/core/instances.rb', line 154

def to_c45(file)
  Saver.save_c45(file: file, instances: self)
end

#to_csv(file) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 137

def to_csv(file)
  Saver.save_csv(file: file, instances: self)
end

#to_json(file) ⇒ Object 



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# File 'lib/weka/core/instances.rb', line 141

def to_json(file)
  Saver.save_json(file: file, instances: self)
end

#to_m ⇒ Matrix

Get the all instances’s values as Matrix.

Returns:

  • (Matrix) —

    a Matrix holding the instance’s values as rows.



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# File 'lib/weka/core/instances.rb', line 274

def to_m
  Matrix[*instances.map(&:values)]
end