# Query syntax

## Overview

Dasel queries are composed of one or more **statements**. Each statement describes how to navigate or transform the data, and the **final statement determines the output value**.

A statement is made up of a sequence of **accessors** or **function calls**, chained together with a dot (`.`) and terminated with a semi-colon (`;`).

* **Accessors** let you step into nested structures (e.g. objects, arrays, maps).
* **Functions** apply transformations or filters to the current value.

### Example

Suppose you have the following JSON document:

```json
{
  "users": [
    {
      "id": 1,
      "name": "Alice",
      "active": true
    },
    {
      "id": 2,
      "name": "Bob",
      "active": false
    }
  ]
}
```

A dasel query might look like this:

```
$activeUsers = $root.users.filter(active == true);
$activeUsers.map(name)
```

* **`$activeUsers =`** \
  Variable assignment.
* **`$root`** \
  Access the root document.
* **`users`**\
  Access the `users` field.
* **`filter(active == true)`**\
  Filter the `users` list to only include elements where `active` is `true`.
* **`;`** \
  Terminate the statement.
* **`$activeUsers`** \
  Access the active users variable we just created.
* **`map`** \
  Iterate through each active user, returning the specified value, in this case `name` .\
  \&#xNAN;*(Since this is the last statement, this is also the **output value**.)*

Output:

```json
[
  "Alice"
]
```

This query could be written in a more compact form, or split into multiple statements for clarity.\
The following examples are equivalent and will all produce the same result:

```
$root.users.filter(active == true).map(name)
```

```
$activeUsers = $root.users.filter(active == true);
$activeUsers.map(name)
```

```
$activeUsers = $root.users.filter(active == true);
$names = $activeUsers.map(name);
$names
```


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# Agent Instructions: Querying This Documentation

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

```
GET https://daseldocs.tomwright.me/syntax/query-syntax.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.