> For the complete documentation index, see [llms.txt](https://data-voyager.gitbook.io/voyager/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://data-voyager.gitbook.io/voyager/visualizing-data/wildcards.md).

# Wildcards

Wildcards let you to precisely vary the properties of a specification to generate multiple visualizations in parallel. There are three types of wildcards: Wildcard Fields, Wildcard Shelves and Wildcard functions.

### Wildcard Fields

Wildcard fields let you create multiple views in parallel by enumerating over a set of fields. Quantitative, Categorical, and Temporal field wildcards are provided by [default](/voyager/visualizing-data/wildcards.md#preset-wildcard-fields), though you can manually author [custom](/voyager/visualizing-data/wildcards.md#custom-wildcard-fields) wildcards containing the desired fields.

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LD8Xv-47Uf0Qc7BSzaT%2F-LD8Xw-N2rOOcneyjDKw%2FScreen%20Shot%202018-05-22%20at%201.30.06%20PM.png?alt=media\&token=acc2f7ba-899d-4ce1-b072-2e0f9a484271)

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LD8Xv-47Uf0Qc7BSzaT%2F-LD8Y4lyTP2SZbKs7WC0%2FScreen%20Shot%202018-05-22%20at%201.30.42%20PM.png?alt=media\&token=0f08d997-e780-4cc0-b18e-90c7ef0d1812)

#### Preset Wildcard Fields

These wildcards represent all fields of a particular data type (Quantitative, Categorical, and Temporal). You can simply drag-and-drop a wildcard field onto an encoding shelf to create multiple charts in parallel. 

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LDSPeJb_LU9Y_b30FB9%2F-LDSPfhrRRo6aalqduXI%2Fwildcard_fields.gif?alt=media\&token=5c73f8ff-a484-4d83-bb8a-5bdf8e6da249)

#### Custom Wildcard Fields

To create a wildcard for a specific set of fields, you can author a custom wildcard field by dragging desired fields to the wildcard list. However, to avoid incongruous views, you are prevented from creating custom wildcard fields that contain multiple data types.

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LDOiGUvmaLxeh4yQJlW%2F-LDOintjA_XG8Rizt_-t%2Fcustom-wildcard-fields.gif?alt=media\&token=71857e0f-2eb0-4958-812c-a351e1f2579d)

### Wildcard Shelves

Wildcard shelves let you add fields without selecting a specific channel, allowing the system to suggest appropriate encodings.

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LDOf4YVLdu5ROa3BnCN%2F-LDOh0_Li_h6oU9cOmts%2Fws.png?alt=media\&token=a4569a60-3428-43c3-ab99-f148416dca73)

The screenshot below shows the system automatically encoding the two quantitative fields onto the `x` and `y` channels since they were the most perceptually effective and expressive channels available.

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LDOf4YVLdu5ROa3BnCN%2F-LDOh3m9lF-YYEJpvGXq%2Fwsgif.gif?alt=media\&token=314c42c3-cc8d-4fb5-89e8-5b122ba8c491)

### Wildcard Function

Wildcard functions allow simultaneous specification of data field transformations. When the `Wildcard` button is checked, the radio buttons for each function will become check-boxes, allowing you to select the functions you want to enumerate. The field pill will denote that it has become a wildcard field by wrapping the field name with with “?”.

![](https://2307510974-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LB2cWom_kyHA9FGG9Zw%2F-LDOf4YVLdu5ROa3BnCN%2F-LDOhFh_qiksNTKHY_q6%2Fwildcard_functions.gif?alt=media\&token=02e6633d-03ea-43e3-9866-713bcac3c023)