Class: Arrow::Table

Inherits:
Object
  • Object
show all
Includes:
ColumnContainable, GenericFilterable, GenericTakeable, RecordContainable
Defined in:
lib/arrow/table.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods included from RecordContainable

#each_record

Methods included from GenericTakeable

included, #take_generic

Methods included from GenericFilterable

#filter_generic, included

Methods included from ColumnContainable

#columns, #each_column, #find_column

Constructor Details

#initialize(columns) ⇒ Table #initialize(raw_table) ⇒ Table #initialize(raw_table) ⇒ Table #initialize(raw_table) ⇒ Table #initialize(schema, columns) ⇒ Table #initialize(schema, arrays) ⇒ Table #initialize(schema, record_batches) ⇒ Table #initialize(schema, raw_records) ⇒ Table

Creates a new Arrow::Table.

Overloads:

  • #initialize(columns) ⇒ Table

    Examples:

    Create a table from columns

    count_field = Arrow::Field.new("count", :uint32)
    count_array = Arrow::UInt32Array.new([0, 2, nil, 4])
    count_column = Arrow::Column.new(count_field, count_array)
    visible_field = Arrow::Field.new("visible", :boolean)
    visible_array = Arrow::BooleanArray.new([true, nil, nil, false])
    visible_column = Arrow::Column.new(visible_field, visible_array)
    Arrow::Table.new([count_column, visible_column])

    Parameters:

  • #initialize(raw_table) ⇒ Table

    Examples:

    Create a table from column name and values

    Arrow::Table.new("count" => Arrow::UInt32Array.new([0, 2, nil, 4]),
                     "visible" => Arrow::BooleanArray.new([true, nil, nil, false]))

    Parameters:

    • raw_table (Hash<String, Arrow::Array>)

      The pairs of column name and values of the table. Column values is `Arrow::Array`.

  • #initialize(raw_table) ⇒ Table

    Examples:

    Create a table from column name and values

    count_chunks = [
      Arrow::UInt32Array.new([0, 2]),
      Arrow::UInt32Array.new([nil, 4]),
    ]
    visible_chunks = [
      Arrow::BooleanArray.new([true]),
      Arrow::BooleanArray.new([nil, nil, false]),
    ]
    Arrow::Table.new("count" => Arrow::ChunkedArray.new(count_chunks),
                     "visible" => Arrow::ChunkedArray.new(visible_chunks))

    Parameters:

    • raw_table (Hash<String, Arrow::ChunkedArray>)

      The pairs of column name and values of the table. Column values is `Arrow::ChunkedArray`.

  • #initialize(raw_table) ⇒ Table

    Examples:

    Create a table from column name and values

    Arrow::Table.new("count" => [0, 2, nil, 4],
                     "visible" => [true, nil, nil, false])

    Parameters:

    • raw_table (Hash<String, ::Array>)

      The pairs of column name and values of the table. Column values is `Array`.

  • #initialize(schema, columns) ⇒ Table

    Examples:

    Create a table from schema and columns

    count_field = Arrow::Field.new("count", :uint32)
    count_array = Arrow::UInt32Array.new([0, 2, nil, 4])
    count_column = Arrow::Column.new(count_field, count_array)
    visible_field = Arrow::Field.new("visible", :boolean)
    visible_array = Arrow::BooleanArray.new([true, nil, nil, false])
    visible_column = Arrow::Column.new(visible_field, visible_array)
    Arrow::Table.new(Arrow::Schema.new([count_field, visible_field]),
                     [count_column, visible_column])

    Parameters:

  • #initialize(schema, arrays) ⇒ Table

    Examples:

    Create a table from schema and arrays

    count_field = Arrow::Field.new("count", :uint32)
    count_array = Arrow::UInt32Array.new([0, 2, nil, 4])
    visible_field = Arrow::Field.new("visible", :boolean)
    visible_array = Arrow::BooleanArray.new([true, nil, nil, false])
    Arrow::Table.new(Arrow::Schema.new([count_field, visible_field]),
                     [count_array, visible_array])

    Parameters:

  • #initialize(schema, record_batches) ⇒ Table

    Examples:

    Create a table from schema and record batches

    count_field = Arrow::Field.new("count", :uint32)
    visible_field = Arrow::Field.new("visible", :boolean)
    schema = Arrow::Schema.new([count_field, visible_field])
    record_batches = [
      Arrow::RecordBatch.new(schema, [[0, true], [2, nil], [nil, nil]]),
      Arrow::RecordBatch.new(schema, [[4, false]]),
    ]
    Arrow::Table.new(schema, record_batches)

    Parameters:

  • #initialize(schema, raw_records) ⇒ Table

    Examples:

    Create a table from schema and raw records

    schema = {
      count: :uint32,
      visible: :boolean,
    }
    raw_records = [
      [0, true],
      [2, nil],
      [nil, nil],
      [4, false],
    ]
    Arrow::Table.new(schema, raw_records)

    Parameters:

    • schema (Arrow::Schema)

      The schema of the table. You can also specify schema as primitive Ruby objects. See Schema#initialize for details.

    • arrays (::Array<::Array>)

      The data of the table as primitive Ruby objects.


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# File 'lib/arrow/table.rb', line 162

def initialize(*args)
  n_args = args.size
  case n_args
  when 1
    raw_table_converter = RawTableConverter.new(args[0])
    schema = raw_table_converter.schema
    values = raw_table_converter.values
  when 2
    schema = args[0]
    schema = Schema.new(schema) unless schema.is_a?(Schema)
    values = args[1]
    case values[0]
    when ::Array
      values = [RecordBatch.new(schema, values)]
    when Column
      values = values.collect(&:data)
    end
  else
    message = "wrong number of arguments (given #{n_args}, expected 1..2)"
    raise ArgumentError, message
  end
  initialize_raw(schema, values)
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ Object


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# File 'lib/arrow/table.rb', line 485

def method_missing(name, *args, &block)
  if args.empty?
    column = find_column(name)
    return column if column
  end
  super
end

Class Method Details

.load(path, options = {}) ⇒ Object


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# File 'lib/arrow/table.rb', line 28

def load(path, options={})
  TableLoader.load(path, options)
end

Instance Method Details

#each_record_batchObject


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# File 'lib/arrow/table.rb', line 186

def each_record_batch
  return to_enum(__method__) unless block_given?

  reader = TableBatchReader.new(self)
  while record_batch = reader.read_next
    yield(record_batch)
  end
end

#group(*keys) ⇒ Object

Experimental


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# File 'lib/arrow/table.rb', line 436

def group(*keys)
  Group.new(self, keys)
end

#inspectObject


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# File 'lib/arrow/table.rb', line 476

def inspect
  "#{super}\n#{to_s}"
end

#inspect_rawObject


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# File 'lib/arrow/table.rb', line 475

alias_method :inspect_raw, :inspect

#merge(other) ⇒ Arrow::Table

TODO

Returns:


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# File 'lib/arrow/table.rb', line 329

def merge(other)
  added_columns = {}
  removed_columns = {}

  case other
  when Hash
    other.each do |name, value|
      name = name.to_s
      if value
        added_columns[name] = ensure_raw_column(name, value)
      else
        removed_columns[name] = true
      end
    end
  when Table
    added_columns = {}
    other.columns.each do |column|
      name = column.name
      added_columns[name] = ensure_raw_column(name, column)
    end
  else
    message = "merge target must be Hash or Arrow::Table: " +
      "<#{other.inspect}>: #{inspect}"
    raise ArgumentError, message
  end

  new_columns = []
  columns.each do |column|
    column_name = column.name
    new_column = added_columns.delete(column_name)
    if new_column
      new_columns << new_column
      next
    end
    next if removed_columns.key?(column_name)
    new_columns << ensure_raw_column(column_name, column)
  end
  added_columns.each do |name, new_column|
    new_columns << new_column
  end
  new_fields = []
  new_arrays = []
  new_columns.each do |new_column|
    new_fields << new_column[:field]
    new_arrays << new_column[:data]
  end
  self.class.new(new_fields, new_arrays)
end

#packObject


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# File 'lib/arrow/table.rb', line 450

def pack
  packed_arrays = columns.collect do |column|
    column.data.pack
  end
  self.class.new(schema, packed_arrays)
end

#remove_column(name_or_index) ⇒ Object


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# File 'lib/arrow/table.rb', line 379

def remove_column(name_or_index)
  case name_or_index
  when String, Symbol
    name = name_or_index.to_s
    index = columns.index {|column| column.name == name}
    if index.nil?
      message = "unknown column: #{name_or_index.inspect}: #{inspect}"
      raise KeyError.new(message)
    end
  else
    index = name_or_index
    index += n_columns if index < 0
    if index < 0 or index >= n_columns
      message = "out of index (0..#{n_columns - 1}): " +
        "#{name_or_index.inspect}: #{inspect}"
      raise IndexError.new(message)
    end
  end
  remove_column_raw(index)
end

#remove_column_rawObject


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# File 'lib/arrow/table.rb', line 378

alias_method :remove_column_raw, :remove_column

#respond_to_missing?(name, include_private) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/arrow/table.rb', line 480

def respond_to_missing?(name, include_private)
  return true if find_column(name)
  super
end

#save(path, options = {}) ⇒ Object


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# File 'lib/arrow/table.rb', line 445

def save(path, options={})
  saver = TableSaver.new(self, path, options)
  saver.save
end

#select_columns(*selectors, &block) ⇒ Arrow::Table

TODO

Returns:


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# File 'lib/arrow/table.rb', line 403

def select_columns(*selectors, &block)
  if selectors.empty?
    return to_enum(__method__) unless block_given?
    selected_columns = columns.select(&block)
  else
    selected_columns = []
    selectors.each do |selector|
      case selector
      when String, Symbol
        column = find_column(selector)
        if column.nil?
          message = "unknown column: #{selector.inspect}: #{inspect}"
          raise KeyError.new(message)
        end
        selected_columns << column
      when Range
        selected_columns.concat(columns[selector])
      else
        column = columns[selector]
        if column.nil?
          message = "out of index (0..#{n_columns - 1}): " +
          "#{selector.inspect}: #{inspect}"
          raise IndexError.new(message)
        end
        selected_columns << column
      end
    end
    selected_columns = selected_columns.select(&block) if block_given?
  end
  self.class.new(selected_columns)
end

#slice(offset, length) ⇒ Arrow::Table #slice(index) ⇒ Arrow::Record #slice(booleans) ⇒ Arrow::Table #slice(boolean_array) ⇒ Arrow::Table #slice(range) ⇒ Arrow::Table #slice {|slicer| ... } ⇒ Arrow::Table

Overloads:

  • #slice(offset, length) ⇒ Arrow::Table

    Returns The sub `Arrow::Table` that covers only from `offset` to `offset + length` range.

    Parameters:

    • offset (Integer)

      The offset of sub Arrow::Table.

    • length (Integer)

      The length of sub Arrow::Table.

    Returns:

    • (Arrow::Table)

      The sub `Arrow::Table` that covers only from `offset` to `offset + length` range.

  • #slice(index) ⇒ Arrow::Record

    Returns The `Arrow::Record` corresponding to index of the table.

    Parameters:

    • index (Integer)

      The index in this table.

    Returns:

    • (Arrow::Record)

      The `Arrow::Record` corresponding to index of the table.

  • #slice(booleans) ⇒ Arrow::Table

    Returns The sub `Arrow::Table` that covers only rows of indices the values of `booleans` is true.

    Parameters:

    • booleans (::Array<Boolean>)

      The values indicating the target rows.

    Returns:

    • (Arrow::Table)

      The sub `Arrow::Table` that covers only rows of indices the values of `booleans` is true.

  • #slice(boolean_array) ⇒ Arrow::Table

    Returns The sub `Arrow::Table` that covers only rows of indices the values of `boolean_array` is true.

    Parameters:

    • boolean_array (::Array<Arrow::BooleanArray>)

      The values indicating the target rows.

    Returns:

    • (Arrow::Table)

      The sub `Arrow::Table` that covers only rows of indices the values of `boolean_array` is true.

  • #slice(range) ⇒ Arrow::Table

    Returns The sub `Arrow::Table` that covers only rows of the range of indices.

    Parameters:

    • range_included_end (Range)

      The range indicating the target rows.

    Returns:

    • (Arrow::Table)

      The sub `Arrow::Table` that covers only rows of the range of indices.

  • #slice {|slicer| ... } ⇒ Arrow::Table

    Returns The sub `Arrow::Table` that covers only rows matched by condition specified by slicer.

    Yields:

    • (slicer)

      Gives slicer that constructs condition to select records.

    Yield Parameters:

    • slicer (Arrow::Slicer)

      The slicer that helps us to build condition.

    Yield Returns:

    Returns:

    • (Arrow::Table)

      The sub `Arrow::Table` that covers only rows matched by condition specified by slicer.


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# File 'lib/arrow/table.rb', line 249

def slice(*args)
  slicers = []
  if block_given?
    unless args.empty?
      raise ArgumentError, "must not specify both arguments and block"
    end
    block_slicer = yield(Slicer.new(self))
    case block_slicer
    when ::Array
      slicers.concat(block_slicer)
    else
      slicers << block_slicer
    end
  else
    expected_n_args = nil
    case args.size
    when 1
      if args[0].is_a?(Integer)
        index = args[0]
        index += n_rows if index < 0
        return nil if index < 0
        return nil if index >= n_rows
        return Record.new(self, index)
      else
        slicers << args[0]
      end
    when 2
      offset, length = args
      slicers << (offset...(offset + length))
    else
      expected_n_args = "1..2"
    end
    if expected_n_args
      message = "wrong number of arguments " +
        "(given #{args.size}, expected #{expected_n_args})"
      raise ArgumentError, message
    end
  end

  filter_options = Arrow::FilterOptions.new
  filter_options.null_selection_behavior = :emit_null
  sliced_tables = []
  slicers.each do |slicer|
    slicer = slicer.evaluate if slicer.respond_to?(:evaluate)
    case slicer
    when Integer
      slicer += n_rows if slicer < 0
      sliced_tables << slice_by_range(slicer, n_rows - 1)
    when Range
      original_from = from = slicer.first
      to = slicer.last
      to -= 1 if slicer.exclude_end?
      from += n_rows if from < 0
      if from < 0 or from >= n_rows
        message =
          "offset is out of range (-#{n_rows + 1},#{n_rows}): " +
          "#{original_from}"
        raise ArgumentError, message
      end
      to += n_rows if to < 0
      sliced_tables << slice_by_range(from, to)
    when ::Array, BooleanArray, ChunkedArray
      sliced_tables << filter(slicer, filter_options)
    else
      message = "slicer must be Integer, Range, (from, to), " +
        "Arrow::ChunkedArray of Arrow::BooleanArray, " +
        "Arrow::BooleanArray or Arrow::Slicer::Condition: #{slicer.inspect}"
      raise ArgumentError, message
    end
  end
  if sliced_tables.size > 1
    sliced_tables[0].concatenate(sliced_tables[1..-1])
  else
    sliced_tables[0]
  end
end

#slice_rawObject


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# File 'lib/arrow/table.rb', line 200

alias_method :slice_raw, :slice

#to_s(options = {}) ⇒ Object


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# File 'lib/arrow/table.rb', line 458

def to_s(options={})
  format = options[:format]
  case format
  when :column
    return to_s_raw
  when :list
    formatter_class = TableListFormatter
  when :table, nil
    formatter_class = TableTableFormatter
  else
    message = ":format must be :column, :list, :table or nil"
    raise ArgumentError, "#{message}: <#{format.inspect}>"
  end
  formatter = formatter_class.new(self, options)
  formatter.format
end

#to_s_rawObject


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# File 'lib/arrow/table.rb', line 457

alias_method :to_s_raw, :to_s

#window(size: nil) ⇒ Object

Experimental


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# File 'lib/arrow/table.rb', line 441

def window(size: nil)
  RollingWindow.new(self, size)
end