Class: Kiba::Extend::Transforms::CombineValues::FromFieldsWithDelimiter

Inherits:
Object
  • Object
show all
Includes:
Allable, SepDeprecatable
Defined in:
lib/kiba/extend/transforms/combine_values/from_fields_with_delimiter.rb

Overview

Combine values from given fields into the target field.

This is like the CONCATENATE function in many spreadsheets. The given delim value is used as a separator between the combined values.

Note: Used with defaults, this has the same function as FullRecord, but deletes the source fields. FullRecord retains source fields by default.

If target field has the same name as one of the source fields, and delete_sources = true, no values are lost. The target field is not deleted.

Blank/nil values are dropped. If prepend_source_field_name = true, names of blank/nil fields are omitted

Examples:

With defaults

# Used in pipeline as:
# transform CombineValues::FromFieldsWithDelimiter
xform = CombineValues::FromFieldsWithDelimiter.new
input = [
  {name: "Weddy", sex: "m", source: "adopted"},
  {source: "hatched", sex: "f", name: "Niblet"},
  {source: "", sex: "m", name: "Tiresias"},
  {name: "Keet", sex: nil, source: "hatched"},
]
result = input.map{ |row| xform.process(row) }
expected = [
  {index: "Weddy m adopted"},
  {index: "Niblet f hatched"},
  {index: "Tiresias m"},
  {index: 'Keet hatched'}
]
expect(result).to eq(expected)

With custom sources, target (with same name as a source field), and delim

# Used in pipeline as:
# transform CombineValues::FromFieldsWithDelimiter,
#  sources: %i[name sex],
#  target: :name,
#  delim: ", "
xform = CombineValues::FromFieldsWithDelimiter.new(
  sources: %i[name sex],
  target: :name,
  delim: ", "
)
input = [
  {name: "Weddy", sex: "m", source: "adopted"},
  {source: "hatched", sex: "f", name: "Niblet"},
  {source: "", sex: "m", name: "Tiresias"},
  {name: "Keet", sex: nil, source: "hatched"},
  {name: "", sex: nil, source: "na"}
]
result = input.map{ |row| xform.process(row) }
expected = [
  {name: "Weddy, m", source: "adopted"},
  {name: "Niblet, f", source: "hatched"},
  {name: "Tiresias, m", source: ""},
  {name: "Keet", source: "hatched"},
  {name: nil, source: "na"}
]
expect(result).to eq(expected)

Direct Known Subclasses

FullRecord

Instance Method Summary collapse

Methods included from SepDeprecatable

#usedelim

Constructor Details

#initialize(sources: :all, target: :index, sep: nil, delim: nil, prepend_source_field_name: false, delete_sources: true) ⇒ FromFieldsWithDelimiter

Returns a new instance of FromFieldsWithDelimiter.

Parameters:

  • sources (Array<Symbol>, :all) (defaults to: :all) —

    Fields whose values are to be combined

  • target (Symbol) (defaults to: :index) —

    Field into which the combined value will be written. May be one of the source fields

  • sep (String) (defaults to: nil) —

    Will be deprecated in a future version. Do not use.

  • delim (String) (defaults to: nil) —

    Value used to separate individual field values in combined target field

  • prepend_source_field_name (Boolean) (defaults to: false) —

    Whether to insert the source field name before its value in the combined value. Since 4.0.0

  • delete_sources (Boolean) (defaults to: true) —

    Whether to delete the source fields after combining their values into the target field. If target field name is the same as one of the source fields, the target field is not deleted. Since 4.0.0



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# File 'lib/kiba/extend/transforms/combine_values/from_fields_with_delimiter.rb', line 89

def initialize(sources: :all, target: :index, sep: nil, delim: nil,
  prepend_source_field_name: false, delete_sources: true)
  @fields = [sources].flatten
  @target = target
  @delim = usedelim(
    sepval: sep,
    delimval: delim,
    calledby: self,
    default: " "
  )
  @del = delete_sources
  @prepend = prepend_source_field_name
end

Instance Method Details

#process(row) ⇒ Object

param row [Hash{ Symbol => String, nil }]



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# File 'lib/kiba/extend/transforms/combine_values/from_fields_with_delimiter.rb', line 104

def process(row)
  finalize_fields(row) unless fields_set

  vals = fields.map { |src| row.fetch(src, nil) }
    .map { |v| v.blank? ? nil : v }

  if prepend
    pvals = []
    vals.each_with_index do |val, i|
      val = "#{fields[i]}: #{val}" unless val.nil?
      pvals << val
    end
    vals = pvals
  end
  val = vals.compact.join(delim)
  row[target] = val.empty? ? nil : val

  fields.each { |src| row.delete(src) unless src == target } if del
  row
end