Class: SelectMap

Inherits:
MapBase show all
Defined in:
lib/mrtoolkit.rb

Overview

Map selects according to a RE

Instance Attribute Summary

Attributes inherited from Stage

#errors, #in_fields, #in_sep, #out_fields, #out_sep

Instance Method Summary collapse

Methods inherited from MapBase

#process_begin, #process_end, #run

Methods inherited from Stage

#catch_errors, #copy_struct, #emit, #emit_separator, #field, #field_separator, #new_input, #new_output, #prepare, #process_step, #write_out

Constructor Details

#initialize(*args) ⇒ SelectMap

Returns a new instance of SelectMap.

Raises:

  • (ArgumentError) 


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# File 'lib/mrtoolkit.rb', line 266

def initialize(*args)
  raise ArgumentError if args.size < 1
  @re = args[0]
  if args[1]
    @field = args[1]
  else
    @field = 0
  end
  if args[2]
    @n = args[2].to_i - 1
  else
    @n = 0
  end
end

Instance Method Details

#declare ⇒ Object 



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# File 'lib/mrtoolkit.rb', line 280

def declare
  (0..@n).each {|i| field "col#{i}"}

  (0..@n).each {|i| emit "col#{i}"}
end

#process(input, output) ⇒ Object 



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# File 'lib/mrtoolkit.rb', line 286

def process(input, output)
  if input[@field] =~ @re
    return copy_struct(input, output)
  end
  nil
end