Contents

# extract subset of columns from CSV
require "csv"

class Masticate::Plucker < Masticate::Base
  def configure(opts)
    standard_options(opts)

    @fields = opts[:fields] or raise "missing fields to pluck"
  end

  def pluck(opts)
    execute(opts)
  end

  def crunch(row)
    if !@headers
      @headers = row
      @indexes = @fields.map do |f|
        case f
        when String
          row.index(f) or raise "Unable to find column '#{f}'"
        when Fixnum
          if f > row.count
            raise "Cannot pluck column #{f}, there are only #{row.count} fields"
          else
            f-1
          end
        else
          raise "Invalid field descriptor '#{f}'"
        end
      end
      @indexes.map {|i| row[i]}
    elsif row
      # output is just the selected columns
      @indexes.map {|i| row[i]}
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
masticate-0.2.1	lib/masticate/plucker.rb