# append-to-list

## Description

<mark style="color:purple;">`append-to-list`</mark> *adaptor adds a single new value to the end of an existing list, or to a new list if the* `list` *input is not specified*.

If you wish to add a value to the beginning of a list, use the [<mark style="color:purple;">`prepend-to-list`</mark> ](https://cgps.gitbook.io/data-flo/reference-guide/prepend-to-list)adaptor. If you wish to add multiple values, use the [<mark style="color:purple;">`append-lists`</mark> ](https://cgps.gitbook.io/data-flo/reference-guide/append-lists)adaptor.

## Inputs

**`list`**\
Type: `list`\
Required: No\
The list to which the values will be appended. If not specified, the value will be added to a new list.

**`value`**\
Type: `text`\
Required: Yes\
The value to be appended to the list.

## Outputs

**`list`**\
Type: `list`\
A list with the value appended.

## Examples

### Example 1: Default behaviour.

#### Inputs:

`value`:

1. `blue`

#### Outputs:

`list`:

1. `blue`

-> Added value `blue` to the end of a new list.

### Example 2: Adding a value to an existing list.

#### Inputs:

`list`:

1. `red`
2. `green`

`value`:

1. `blue`

#### Outputs:

`list`:

1. `red`
2. `green`
3. `blue`

-> Added value `blue` to the end of an existing list.

## Use Cases

* Add a new species to a list of reportable illnesses.
* After using the [<mark style="color:purple;">`sort list`</mark> ](https://cgps.gitbook.io/data-flo/reference-guide/sort-list)adaptor, add a missing element to the end of the list.
* Adding new values to lists allows for adjustment of included values without modifying the original dataset.
* Users might need to dynamically add new values to a list based on changing programme priorities or newly mapped values, or missed/forgotten values to include.
* Allows for users to include additional observations, experiment with different scenarios, or respond to changes in the data.
* Lists are often used to keep track of records or historical data. Adding new values ensures that the record is comprehensive and up-to-date.


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