Class: IOStreams::Record::Writer

Inherits:
Object
  • Object
show all
Defined in:
lib/io_streams/record/writer.rb

Overview

Example, implied header from first record:

IOStreams.record_writer do |stream|
  stream << {name: 'Jack', address: 'Somewhere', zipcode: 12345}
  stream << {name: 'Joe', address: 'Lost', zipcode: 32443, age: 23}
end

Output:

name, add

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(delimited, columns: nil, **args) ⇒ Writer

Create a Tabular writer that takes individual Parse a delimited data source.

Parameters

delimited: [#<<]
  Anything that accepts a line / record at a time when #<< is called on it.

format: [Symbol]
  :csv, :hash, :array, :json, :psv, :fixed

For all other parameters, see Tabular::Header.new

  columns: nil, allowed_columns: nil, required_columns: nil, skip_unknown: true)



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# File 'lib/io_streams/record/writer.rb', line 42

def initialize(delimited, columns: nil, **args)
  @tabular   = IOStreams::Tabular.new(columns: columns, **args)
  @delimited = delimited

  # Render header line when `columns` is supplied.
  @delimited << @tabular.render_header if columns && @tabular.requires_header?
end

Class Method Details

.open(file_name_or_io, delimiter: $/, encoding: nil, encode_cleaner: nil, encode_replace: nil, **args) ⇒ Object

Write a record as a Hash at a time to a file or stream.



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# File 'lib/io_streams/record/writer.rb', line 14

def self.open(file_name_or_io, delimiter: $/, encoding: nil, encode_cleaner: nil, encode_replace: nil, **args)
  if file_name_or_io.is_a?(String)
    IOStreams.line_writer(file_name_or_io,
                          delimiter:      delimiter,
                          encoding:       encoding,
                          encode_cleaner: encode_cleaner,
                          encode_replace: encode_replace
    ) do |io|
      yield new(io, file_name: file_name_or_io, **args)
    end
  else
    yield new(file_name_or_io, **args)
  end
end

Instance Method Details

#<<(hash) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/io_streams/record/writer.rb', line 50

def <<(hash)
  raise(ArgumentError, 'Must supply a Hash') unless hash.is_a?(Hash)
  if @tabular.header?
    # Extract header from the keys from the first row when not supplied above.
    @tabular.header.columns = hash.keys
    @delimited << @tabular.render_header
  end
  @delimited << @tabular.render(hash)
end