# Maps and arrays Functions

## Introduction

XPath 3.1 introduces [maps](https://www.w3.org/TR/xpath-31/#id-maps) and [arrays](https://www.w3.org/TR/xpath-31/#id-arrays). Orbeon Forms does not support XPath 3.1 yet, however it implements a subset of operations on maps and arrays.

## Availability

\[SINCE Orbeon Forms 2017.2]

### Maps

#### Introduction

Orbeon Forms does not support the native XPath 3.1 syntax to create maps. But you can create a new map as follows using the `map:merge()` and `map:entry()` functions:

```
map:merge(
    (
        map:entry('number',   42),
        map:entry('string',   'forty-two'),
        map:entry('node',     instance()),
        map:entry('sequence', 1 to 10)
    )
)
```

#### map:entry()

```
map:entry(
    $key as xs:anyAtomicType,
    $value as item()*
) as map(*)
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-map-entry).

#### map:merge()

```
map:merge($maps as map(*)*) as map(*)
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-map-merge).

#### map:get()

```
map:get(
    $map as map(*),
    $key as xs:anyAtomicType
) as item()*
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-map-get).

### Arrays

#### Introduction

Orbeon Forms does not support the native XPath 3.1 syntax to create arrays. But you can create a new array as follows using the `array:join()` and `array:append()` functions:

```
array:append(
    array:append(
        array:append(
            array:append(
                array:join(()),
                42
            ),
            'forty-two'
        ),
        instance()
    ),
    1 to 10
)
```

#### array:size()

```
array:size($array as array(*)) as xs:integer
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-array-size).

#### array:get()

```
array:get($array as array(*), $position as xs:integer) as item()*
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-array-get).

#### array:put()

```
array:put(
    $array    as array(*),
    $position as xs:integer,
    $member   as item()*
) as array(*)
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-array-put).

#### array:append()

```
array:append(
    $array     as array(*),
    $appendage as item()*
) as array(*)
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-array-append).

#### array:join()

```
array:join($arrays as array(*)*) as array(*)
```

[XPath 3.1 documentation](https://www.w3.org/TR/xpath-functions-31/#func-array-join).


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://doc.orbeon.com/xforms/xpath/maps-arrays.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.