# Dynamic

## Description

Dynamic selectors allow you to select items from lists or maps when you don't know the key or index. You can think of this as searching the current node.

## Usage

{% hint style="info" %}
You can use a selector as the key to create more complex conditions.
{% endhint %}

```shell
.(<key>=<value>)
```

### Key

The key defines which property/selector we should use to extract a value.

If `<key>` is:

* `.` or `value` - dasel checks if the current nodes value is `<value>`.
* `-` or `keyValue` - dasel checks if the key/name/index of the current node is `<value>`.
* Else dasel uses the key as a selector itself and compares the result against `<value>`.

### Value

The value is the expected value for the check to pass.

Note that dasel will stringy values prior to checking if they match.

### Comparisons

Dasel supports the following comparison operators:

| Operator | Supported since |
| -------- | --------------- |
| `=`      | `v0.0.4`        |
| `>=`     | `v1.14.0`       |
| `>`      | `v1.14.0`       |
| `<`      | `v1.14.0`       |
| `<=`     | `v1.14.0`       |
| `!=`     | `v1.17.0`       |

### Multiple conditions

You can use multiple dynamic selectors within the same part to perform `AND` logic.

```shell
.(<key>=<value>)(<key2>=<value2>)
```

### Non-object values

You can evaluate and check against non-object values by defining the `key` as either `value` or `.`. Doing so will tell dasel extract the value of the current node and compare that against `<value>`.

### Selectors as a key

When performing dynamic checks dasel internally creates a new root node at the current position and queries data from there.

This means that you can use fully formed selectors as a key to create more advanced logic.

```shell
.users.(.addresses.(.primary=true).number=123).name.first
```

The above selector in plain English may read as...

> Give me the first name of the user who's primary address is at number 123.

The resolution of that query looks something like this:

```
.users.(.addresses.(.primary=true).number=123).name.first
.users.(.addresses.[0].number=123).name.first
.users.[0].name.first
```

## Example

{% code title="simple:input.yaml" %}

```yaml
colourCodes:
  - name: red
    rgb: ff0000
  - name: green
    rgb: 00ff00
  - name: blue
    rgb: 0000ff
```

{% endcode %}

{% code title="advanced:input.json" %}

```json
{
  "users": [
    {
      "name": {
        "first": "Tom",
        "last": "Wright"
      },
      "addresses": [
        {
          "primary": true,
          "number": 123
        },
        {
          "primary": false,
          "number": 456
        }
      ]
    }
  ]
}
```

{% endcode %}

### Single condition

```shell
$ dasel select -f simple_input.yaml '.colourCodes.(name=red).rgb'
ff0000
```

### Multiple conditions

```shell
$ dasel select -f simple_input.yaml '.colourCodes.(name=red)(rgb=ff0000).rgb'
ff0000
```

### Selector as a key

```shell
$ dasel -f advanced_input.json '.users.(.addresses.(.primary=true).number=123).name.first'
"Tom"
```


---

# 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://daseldocs.tomwright.me/v1/selectors/dynamic.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.