Nest Transform
注記
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: |
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:
objectarray
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
ヒント
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 | |
|---|---|
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"} |