Class: Kiba::Extend::Transforms::Explode::RowsFromGroupedMultivalFields

Inherits:
Object
  • Object
show all
Defined in:
lib/kiba/extend/transforms/explode/rows_from_grouped_multival_fields.rb

Overview

Creates a new row for each value position in a multivalued field group. For instance, if the values in “name” and “role” fields repeat together, this will create a row with the first values of “name” and “role”, another row for the second values of “name” and “role”, and so on.

If the number of values in grouped multivalued fields is uneven (e.g. 3 names, but 2 roles), the missing values in the later rows will be nil, or the placeholder string value if given.

Note that:

  • If the value of any grouped fields is nil or an empty string, that field, for the affected row, is treated like any other field in the row (i.e. not part of the group).
  • Empty/missing values delimited as such in a multivalued grouped field get treated as empty string values.

Examples:

With defaults

# Used in pipeline as:
# transform Explode::RowsFromGroupedMultivalFields,
#   fields: %i[name role]
xform = Explode::RowsFromGroupedMultivalFields.new(
  fields: %i[name role]
)
input = [
  {id: "1", name: "Acme|Smith|Bond", role: "pub|pub|prt"},
  {id: "2", name: "Acme|Smith|Bond", role: "pub||prt"},
  {id: "3", name: "Acme|Smith|Bond", role: "pub|prt"},
  {id: "3.5", name: "Acme|Smith|Bond", role: "|pub|prt"},
  {id: "3.6", name: "Acme|Smith|Bond", role: "pub|prt|"},
  {id: "4", name: "Acme||Bond", role: "pub|pub|prt"},
  {id: "5", name: "Acme|Smith", role: "pub|pub|prt"},
  {id: "6", name: "Acme|Smith|Bond", role: ""},
  {id: "7", name: nil, role: "pub|pub|prt"},
  {id: "8", name: nil, role: nil},
]
result = Kiba::StreamingRunner.transform_stream(input, xform)
  .map{ |row| row }
expected = [
  {id: "1", name: "Acme", role: "pub"},
  {id: "1", name: "Smith", role: "pub"},
  {id: "1", name: "Bond", role: "prt"},
  {id: "2", name: "Acme", role: "pub"},
  {id: "2", name: "Smith", role: ""},
  {id: "2", name: "Bond", role: "prt"},
  {id: "3", name: "Acme", role: "pub"},
  {id: "3", name: "Smith", role: "prt"},
  {id: "3", name: "Bond", role: nil},
  {id: "3.5", name: "Acme", role: ""},
  {id: "3.5", name: "Smith", role: "pub"},
  {id: "3.5", name: "Bond", role: "prt"},
  {id: "3.6", name: "Acme", role: "pub"},
  {id: "3.6", name: "Smith", role: "prt"},
  {id: "3.6", name: "Bond", role: ""},
  {id: "4", name: "Acme", role: "pub"},
  {id: "4", name: "", role: "pub"},
  {id: "4", name: "Bond", role: "prt"},
  {id: "5", name: "Acme", role: "pub"},
  {id: "5", name: "Smith", role: "pub"},
  {id: "5", name: nil, role: "prt"},
  {id: "6", name: "Acme", role: ""},
  {id: "6", name: "Smith", role: ""},
  {id: "6", name: "Bond", role: ""},
  {id: "7", name: nil, role: "pub"},
  {id: "7", name: nil, role: "pub"},
  {id: "7", name: nil, role: "prt"},
  {id: "8", name: nil, role: nil}
]
expect(result).to eq(expected)

With placeholder

# Used in pipeline as:
# transform Explode::RowsFromGroupedMultivalFields,
#   fields: %i[name role],
#   placeholder: "NULL"
xform = Explode::RowsFromGroupedMultivalFields.new(
  fields: %i[name role], placeholder: "NULL"
)
input = [
  {id: "1", name: "Acme|Smith|Bond", role: "pub|pub|prt"},
  {id: "2", name: "Acme|Smith|Bond", role: "pub||prt"},
  {id: "3", name: "Acme|Smith|Bond", role: "pub|prt"},
  {id: "4", name: "Acme||Bond", role: "pub|pub|prt"},
  {id: "5", name: "Acme|Smith", role: "pub|pub|prt"},
  {id: "6", name: "Acme|Smith|Bond", role: ""},
  {id: "7", name: nil, role: "pub|pub|prt"},
  {id: "8", name: nil, role: nil},
]
result = Kiba::StreamingRunner.transform_stream(input, xform)
  .map{ |row| row }
expected = [
  {id: "1", name: "Acme", role: "pub"},
  {id: "1", name: "Smith", role: "pub"},
  {id: "1", name: "Bond", role: "prt"},
  {id: "2", name: "Acme", role: "pub"},
  {id: "2", name: "Smith", role: ""},
  {id: "2", name: "Bond", role: "prt"},
  {id: "3", name: "Acme", role: "pub"},
  {id: "3", name: "Smith", role: "prt"},
  {id: "3", name: "Bond", role: "NULL"},
  {id: "4", name: "Acme", role: "pub"},
  {id: "4", name: "", role: "pub"},
  {id: "4", name: "Bond", role: "prt"},
  {id: "5", name: "Acme", role: "pub"},
  {id: "5", name: "Smith", role: "pub"},
  {id: "5", name: "NULL", role: "prt"},
  {id: "6", name: "Acme", role: ""},
  {id: "6", name: "Smith", role: ""},
  {id: "6", name: "Bond", role: ""},
  {id: "7", name: nil, role: "pub"},
  {id: "7", name: nil, role: "pub"},
  {id: "7", name: nil, role: "prt"},
  {id: "8", name: nil, role: nil}
]
expect(result).to eq(expected)

Since:

  • 4.0.0

Instance Method Summary collapse

Constructor Details

#initialize(fields:, delim: nil, placeholder: nil) ⇒ RowsFromGroupedMultivalFields

Returns a new instance of RowsFromGroupedMultivalFields.

Parameters:

  • fields (Symbol) —

    the grouped fields from which rows will be created

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

    used to split field value. Kiba::Extend.delim used if value not given

  • placeholder (nil, String) (defaults to: nil) —

    used in empty field values when number of values in grouped fields are not equal

Since:

  • 4.0.0



132
133
134
135
136
137
 
# File 'lib/kiba/extend/transforms/explode/rows_from_grouped_multival_fields.rb', line 132

def initialize(fields:, delim: nil, placeholder: nil)
  @fields = [fields].flatten
  @delim = delim || Kiba::Extend.delim
  @placeholder = placeholder
  @other_fields = nil
end

Instance Method Details

#process(row) ⇒ Object

Parameters:

  • row (Hash{ Symbol => String, nil })

Since:

  • 4.0.0



140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
 
# File 'lib/kiba/extend/transforms/explode/rows_from_grouped_multival_fields.rb', line 140

def process(row)
  set_other_fields(row) unless other_fields
  other_field_vals = field_vals(row, other_fields)
  orig_vals = get_orig_vals(row)

  handle_unpopulated_vals(orig_vals[true], other_field_vals)
  split_vals = do_val_splits(orig_vals[false])

  if split_vals
    split_vals.each { |sval| yield other_field_vals.merge(sval) }
  else
    yield row
  end
  nil
end