Class: Kiba::Extend::Transforms::Delete::FieldsExcept

Inherits:
Object
  • Object
show all
Defined in:
lib/kiba/extend/transforms/delete/fields_except.rb

Overview

Deletes all fields except the one(s) passed in fields parameter.

Examples

Input table:

| a | b | c |
|---+---+---|
| 1 | 2 | 3 |

Used in pipeline as:

transform Delete::FieldsExcept, fields: %i[a c]

Results in:

| a | c |
|---+---|
| 1 | 3 |

Used in pipeline as:

transform Delete::FieldsExcept, fields: :b

Results in:

| b |
|---|
| 2 |

Defined Under Namespace

Classes: MissingKeywordArgumentError

Instance Method Summary collapse

Constructor Details

#initialize(keepfields: nil, fields: nil) ⇒ FieldsExcept

Note:

The keepfields parameter will be deprecated in a future version. Use fields in new code.

Returns a new instance of FieldsExcept.

Parameters:

  • keepfields (Array<Symbol>, Symbol, nil) (defaults to: nil) —

    DEPRECATED; DO NOT USE

  • fields (Array<Symbol>, Symbol, nil) (defaults to: nil) —

    list of fields to keep

Raises:



63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
 
# File 'lib/kiba/extend/transforms/delete/fields_except.rb', line 63

def initialize(keepfields: nil, fields: nil)
  if keepfields && fields
    puts Kiba::Extend.warn(
      "Do not use both `keepfields` and `fields`. Defaulting to "\
        "process using `fields`"
    )
    @fields = [fields].flatten
  elsif keepfields
    puts Kiba::Extend.warn(
      "The `keepfields` keyword is being deprecated in a future "\
        "version. Change it to `fields` in your ETL code."
    )
    @fields = [keepfields].flatten
  elsif fields
    @fields = [fields].flatten
  else
    raise MissingKeywordArgumentError
  end
end

Instance Method Details

#process(row) ⇒ Object

Parameters:

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


84
85
86
87
88
 
# File 'lib/kiba/extend/transforms/delete/fields_except.rb', line 84

def process(row)
  deletefields = row.keys - fields
  deletefields.each { |f| row.delete(f) }
  row
end