Class: SparkConnect::Row

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/spark_connect/row.rb

Overview

An ordered collection of named fields representing a single row of a DataFrame, returned by DataFrame#collect, DataFrame#take, etc.

Fields are accessible positionally (‘row`), by name (`row` or `row.id`), and the whole row converts cleanly to a Hash or Array.

Examples:

row = SparkConnect::Row.new({ "id" => 1, "name" => "alice" })
row[0]        #=> 1
row["name"]   #=> "alice"
row.name      #=> "alice"
row.to_h      #=> {"id"=>1, "name"=>"alice"}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(hash) ⇒ Row #initialize(values, fields:) ⇒ Row

Returns a new instance of Row.

Overloads:

  • #initialize(hash) ⇒ Row

    Parameters:

    • hash (Hash) —

      an ordered mapping of field name to value.

  • #initialize(values, fields:) ⇒ Row

    Parameters:

    • values (Array) —

      positional values

    • fields (Array<String>) —

      field names



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# File 'lib/spark_connect/row.rb', line 30

def initialize(data = {}, fields: nil)
  if fields
    @fields = fields.map(&:to_s)
    @values = data
  else
    @fields = data.keys.map(&:to_s)
    @values = data.values
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args) ⇒ Object

Allows ‘row.field_name` access for field names that are valid method names.



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# File 'lib/spark_connect/row.rb', line 87

def method_missing(name, *args)
  key = name.to_s
  if args.empty? && @fields.include?(key)
    self[key]
  else
    super
  end
end

Instance Attribute Details

#fields ⇒ Array<String> (readonly)

Returns the field names, in order.

Returns:

  • (Array<String>) —

    the field names, in order.



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# File 'lib/spark_connect/row.rb', line 20

def fields
  @fields
end

#values ⇒ Array (readonly)

Returns the field values, in order.

Returns:

  • (Array) —

    the field values, in order.



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# File 'lib/spark_connect/row.rb', line 23

def values
  @values
end

Instance Method Details

#==(other) ⇒ Object Also known as: eql? 



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# File 'lib/spark_connect/row.rb', line 79

def ==(other)
  other.is_a?(Row) && other.fields == fields && other.values == values
end

#[](key) ⇒ Object?

Look up a value by zero-based index or by field name.

Parameters:

  • key (Integer, String, Symbol)

Returns:

  • (Object, nil) 


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# File 'lib/spark_connect/row.rb', line 44

def [](key)
  case key
  when Integer then @values[key]
  else
    idx = @fields.index(key.to_s)
    idx && @values[idx]
  end
end

#each ⇒ Object

Iterate over the values in order.



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# File 'lib/spark_connect/row.rb', line 65

def each(&) = @values.each(&)

#field(name) ⇒ Object

Returns the value for ‘name`, raising if the field is absent.

Returns:

  • (Object) —

    the value for ‘name`, raising if the field is absent.

Raises:



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# File 'lib/spark_connect/row.rb', line 72

def field(name)
  idx = @fields.index(name.to_s)
  raise IllegalArgumentError, "No such field: #{name}" unless idx

  @values[idx]
end

#hash ⇒ Object 



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# File 'lib/spark_connect/row.rb', line 84

def hash = [fields, values].hash

#length ⇒ Integer Also known as: size

Returns number of fields.

Returns:

  • (Integer) —

    number of fields.



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# File 'lib/spark_connect/row.rb', line 68

def length = @values.length

#respond_to_missing?(name, include_private = false) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spark_connect/row.rb', line 96

def respond_to_missing?(name, include_private = false)
  @fields.include?(name.to_s) || super
end

#to_a ⇒ Array

Returns the row’s values, in order.

Returns:

  • (Array) —

    the row’s values, in order.



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# File 'lib/spark_connect/row.rb', line 60

def to_a
  @values.dup
end

#to_h ⇒ Hash Also known as: as_dict

Returns an ordered Hash of field name to value.

Returns:

  • (Hash) —

    an ordered Hash of field name to value.



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# File 'lib/spark_connect/row.rb', line 54

def to_h
  @fields.zip(@values).to_h
end

#to_s ⇒ Object Also known as: inspect 



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# File 'lib/spark_connect/row.rb', line 100

def to_s
  "Row(#{@fields.zip(@values).map { |k, v| "#{k}=#{v.inspect}" }.join(', ')})"
end