Class: Charty::TableAdapters::BaseAdapter

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Enumerable
Defined in:
lib/charty/table_adapters/base_adapter.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#columns ⇒ Object

Returns the value of attribute columns.



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# File 'lib/charty/table_adapters/base_adapter.rb', line 9

def columns
  @columns
end

#index ⇒ Object

Returns the value of attribute index.



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# File 'lib/charty/table_adapters/base_adapter.rb', line 32

def index
  @index
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 38

def ==(other)
  case other
  when BaseAdapter
    return false if columns != other.columns
    return false if index != other.index
    compare_data_equality(other)
  else
    false
  end
end

#column?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/charty/table_adapters/base_adapter.rb', line 19

def column?(name)
  return true if column_names.include?(name)

  case name
  when String
    column_names.include?(name.to_sym)
  when Symbol
    column_names.include?(name.to_s)
  else
    false
  end
end

#column_names ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 15

def column_names
  columns.to_a
end

#compare_data_equality(other) ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 53

def compare_data_equality(other)
  columns.each do |name|
    if self[nil, name] != other[nil, name]
      return false
    end
  end
  true
end

#drop_na ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 62

def drop_na
  # TODO: Must implement this method in each adapter
  missing_index = index.select do |i|
    column_names.any? do |key|
      Util.missing?(self[i, key])
    end
  end
  if missing_index.empty?
    nil
  else
    select_index = index.to_a - missing_index
    new_data = column_names.map { |key|
      vals = select_index.map {|i| self[i, key] }
      [key, vals]
    }.to_h
    Charty::Table.new(new_data, index: select_index)
  end
end

#group_by(table, grouper, sort, drop_na) ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 49

def group_by(table, grouper, sort, drop_na)
  Table::HashGroupBy.new(table, grouper, sort, drop_na)
end

#melt(id_vars: nil, value_vars: nil, var_name: nil, value_name: :value) ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 142

def melt(id_vars: nil, value_vars: nil, var_name: nil, value_name: :value)
  if column?(value_name)
    raise ArgumentError,
          "The value of `value_name` must not be matched to the existing column names."
  end

  case value_name
  when Symbol
    # do nothing
  else
    value_name = value.to_str.to_sym
  end

  id_vars = check_melt_vars(id_vars, :id_vars)
  value_vars = check_melt_vars(value_vars, :value_vars) { self.column_names }
  value_vars -= id_vars

  case var_name
  when nil
    var_name = self.columns.name
    var_name = :variable if var_name.nil?
  when Symbol
    # do nothing
  else
    var_name = var_name.to_str
  end
  var_name = var_name.to_sym

  n_batch_rows = self.length
  n_target_columns = value_vars.length
  melted_data = id_vars.map { |cn|
    id_values = self[nil, cn].to_a
    [cn.to_sym, id_values * n_target_columns]
  }.to_h

  melted_data[var_name] = value_vars.map { |cn| Array.new(n_batch_rows, cn) }.flatten

  melted_data[value_name] = value_vars.map { |cn| self[nil, cn].to_a }.flatten

  Charty::Table.new(melted_data)
end

#sort_values(by, na_position: :last) ⇒ Object 



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# File 'lib/charty/table_adapters/base_adapter.rb', line 81

def sort_values(by, na_position: :last)
  na_cmp_val = check_na_position(na_position)
  case by
  when String, Symbol
    order = (0 ... length).sort do |i, j|
      a = self[i, by]
      b = self[j, by]
      case
      when Util.missing?(a)  # missing > b
        na_cmp_val
      when Util.missing?(b)  # a < missing
        -na_cmp_val
      else
        cmp = a <=> b
        if cmp == 0
          i <=> j
        else
          cmp
        end
      end
    end
  when Array
    order = (0 ... length).sort do |i, j|
      cmp = 0
      by.each do |key|
        a = self[i, key]
        b = self[j, key]
        case
        when Util.missing?(a)  # missing > b
          cmp = na_cmp_val
          break
        when Util.missing?(b)  # a < missing
          cmp = -na_cmp_val
          break
        else
          cmp = a <=> b
          break if cmp != 0
        end
      end
      if cmp == 0
        i <=> j
      else
        cmp
      end
    end
  else
    raise ArgumentError,
          "%p is invalid value for `by`" % by
  end

  Charty::Table.new(
    column_names.map { |name|
      [
        name,
        self[nil, name].values_at(*order)
      ]
    }.to_h,
    index: index.to_a.values_at(*order)
  )
end