Method: Sequel::Dataset#map

Defined in:
lib/sequel/dataset/actions.rb

#map(column = nil, &block) ⇒ Object

Maps column values for each record in the dataset (if a column name is given), or performs the stock mapping functionality of Enumerable otherwise. Raises an Error if both an argument and block are given.

DB[:table].map(:id) # SELECT * FROM table
# => [1, 2, 3, ...]

DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table
# => [2, 4, 6, ...]



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# File 'lib/sequel/dataset/actions.rb', line 337

def map(column=nil, &block)
  if column
    raise(Error, ARG_BLOCK_ERROR_MSG) if block
    super(){|r| r[column]}
  else
    super(&block)
  end
end