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Nest Transform

Nota

Transforms are a part of the underlying language, which is not directly accessible to users. This content is maintained for reference purposes only. For more information on the user-accessible equivalent to transforms, see Transformation Reference.

Creates an Object or Array of values using column names and their values as key-value pairs for one or more columns. Generated column type is determined by the into parameter.

The nest transform is the opposite of unnest, which unpacks Object data into separate columns and rows. See Unnest Transform.

Basic Usage

ItemA

ItemB

22

33

44

55

Object example:

nest col:ItemA,ItemB into:'obj' as:'myObj'

Output: See below.

ItemA

ItemB

myObj

22

33

{"ItemA":"22","ItemB","33"}

44

55

{"ItemA":"44","ItemB","55"}

Array example:

nest col:ItemA,ItemB into:'array' as:'myArray'

Output: Output arrays do not include the column name.

ItemA

ItemB

myArray

22

33

["22","33"]

44

55

["44","55"]

Syntax and Parameters

nest col:column_ref [into: object|array] [as:'new_column_name']

Token

Required?

Data Type

Description

nest

Y

transform

Name of the transform

col

Y

string

Source column name

into

N

string

Data type of output column: object (default) or array

as

N

string

Name of newly generated column

For more information on syntax standards, see Language Documentation Syntax Notes.

col

Identifies the column or columns to which to apply the transform. You can specify one column or more columns.

To specify multiple columns:

  • Discrete column names are comma-separated.

  • Values for column names are case-sensitive.

For each listed column, a new pair of key and value columns is generated.

nest col: Qty, Amount

Output: Builds an Object of the data from the columns Qty and Amount .

Usage Notes:

Required?

Data Type

Yes

String (column name)

into

Defines the output column type. Accepted values:

  • object

  • array

If this parameter is not specified, the output type is Object.

Usage Notes:

Required?

Data Type

No (Object is default)

String (data type name)

as

Name of the new column that is being generated. If the as parameter is not specified, a default name is used.

nest col: CustId,ProdId as:'masterNest'

Output: Nests the data from the columns CustId and ProdId into a new column called, masterNest.

Usage Notes:

Required?

Data Type

No

String (column name)

Examples

Suggerimento

For additional examples, see Common Tasks.

Source:

In the following example, furniture product dimensions are stored in separate columns in cm.

Category

Name

Length_cm

Width_cm

Height_cm

bench

Hooska

118.11

74.93

46.34

lamp

Tansk

30.48

30.48

165.1

bookshelf

Brock

27.94

160.02

201.93

couch

Loafy

95

227

83

Transformation:

Use the nest transform to bundle the data into a single column.

Transformation Name

Nest columns into Objects

Parameter: Columns

Length_cm,Width_cm,Height_cm

Parameter: Nest columns to

Array

Parameter: New column name

'Dimensions'

Results:

Category

Name

Length_cm

Width_cm

Height_cm

Dimensions

bench

Hooska

118.11

74.93

46.34

{"Length_cm":"118.11","Width_cm":"74.93","Height_cm":"46.34"}

lamp

Tansk

30.48

30.48

165.1

{"Length_cm":"30.48","Width_cm":"30.48","Height_cm":"165.1"}

bookshelf

Brock

27.94

160.02

201.93

{"Length_cm":"27.94","Width_cm":"160.02","Height_cm":"201.93"}

couch

Loafy

95

227

83

{"Length_cm":"95,"Width_cm":"227","Height_cm":"83"}