# Trait yii\base\ArrayableTrait

Implemented by | yii\base\DynamicModel, yii\base\Model, yii\data\ActiveDataFilter, yii\data\DataFilter, yii\db\ActiveRecord, yii\db\BaseActiveRecord, yii\debug\models\Router, yii\debug\models\UserSwitch, yii\debug\models\router\ActionRoutes, yii\debug\models\router\CurrentRoute, yii\debug\models\router\RouterRules, yii\debug\models\search\Base, yii\debug\models\search\Db, yii\debug\models\search\Debug, yii\debug\models\search\Event, yii\debug\models\search\Log, yii\debug\models\search\Mail, yii\debug\models\search\Profile, yii\debug\models\search\User, yii\debug\models\timeline\Search, yii\elasticsearch\ActiveRecord, yii\gii\Generator, yii\gii\generators\controller\Generator, yii\gii\generators\crud\Generator, yii\gii\generators\extension\Generator, yii\gii\generators\form\Generator, yii\gii\generators\model\Generator, yii\gii\generators\module\Generator, yii\httpclient\debug\SearchModel, yii\mongodb\ActiveRecord, yii\mongodb\file\ActiveRecord, yii\mongodb\gii\model\Generator, yii\redis\ActiveRecord, yii\sphinx\ActiveRecord, yii\sphinx\gii\model\Generator
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/base/ArrayableTrait.php

ArrayableTrait provides a common implementation of the yii\base\Arrayable interface.

ArrayableTrait implements toArray() by respecting the field definitions as declared in fields() and extraFields().

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
extraFields() | Returns the list of fields that can be expanded further and returned by toArray(). | yii\base\ArrayableTrait
fields() | Returns the list of fields that should be returned by default by toArray() when no specific fields are specified. | yii\base\ArrayableTrait
toArray() | Converts the model into an array. | yii\base\ArrayableTrait

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
extractFieldsFor() | Extract nested fields from a fields collection for a given root field Nested fields are separated with dots (.). e.g: "item.id" The previous example would extract "id". | yii\base\ArrayableTrait
extractRootFields() | Extracts the root field names from nested fields. | yii\base\ArrayableTrait
resolveFields() | Determines which fields can be returned by toArray(). | yii\base\ArrayableTrait

## Method Details

extraFields() public method

Returns the list of fields that can be expanded further and returned by toArray().

This method is similar to fields() except that the list of fields returned by this method are not returned by default by toArray(). Only when field names to be expanded are explicitly specified when calling toArray(), will their values be exported.

The default implementation returns an empty array.

You may override this method to return a list of expandable fields based on some context information (e.g. the current application user).

See also:

- toArray()
- fields()

public array extraFields ( )
return | array | The list of expandable field names or field definitions. Please refer to fields() on the format of the return value.

extractFieldsFor() protected method (available since version 2.0.14)

Extract nested fields from a fields collection for a given root field Nested fields are separated with dots (.). e.g: "item.id" The previous example would extract "id".

protected array extractFieldsFor ( array $fields, $rootField )
$fields | array | The fields requested for extraction
$rootField | string | The root field for which we want to extract the nested fields
return | array | Nested fields extracted for the given field

extractRootFields() protected method (available since version 2.0.14)

Extracts the root field names from nested fields.

Nested fields are separated with dots (.). e.g: "item.id" The previous example would extract "item".

protected array extractRootFields ( array $fields )
$fields | array | The fields requested for extraction
return | array | Root fields extracted from the given nested fields

fields() public method

Returns the list of fields that should be returned by default by toArray() when no specific fields are specified.

A field is a named element in the returned array by toArray().

This method should return an array of field names or field definitions. If the former, the field name will be treated as an object property name whose value will be used as the field value. If the latter, the array key should be the field name while the array value should be the corresponding field definition which can be either an object property name or a PHP callable returning the corresponding field value. The signature of the callable should be:

    function ($model, $field) {
        // return field value
    }

For example, the following code declares four fields:

- `email`: the field name is the same as the property name `email`;
- `firstName` and `lastName`: the field names are `firstName` and `lastName`, and their values are obtained from the `first_name` and `last_name` properties;
- `fullName`: the field name is `fullName`. Its value is obtained by concatenating `first_name` and `last_name`.

    return [
        'email',
        'firstName' => 'first_name',
        'lastName' => 'last_name',
        'fullName' => function () {
            return $this->first_name . ' ' . $this->last_name;
        },
    ];

In this method, you may also want to return different lists of fields based on some context information. For example, depending on the privilege of the current application user, you may return different sets of visible fields or filter out some fields.

The default implementation of this method returns the public object member variables indexed by themselves.

See also toArray().

public array fields ( )
return | array | The list of field names or field definitions.

resolveFields() protected method

Determines which fields can be returned by toArray().

This method will first extract the root fields from the given fields. Then it will check the requested root fields against those declared in fields() and extraFields() to determine which fields can be returned.

protected array resolveFields ( array $fields, array $expand )
$fields | array | The fields being requested for exporting
$expand | array | The additional fields being requested for exporting
return | array | The list of fields to be exported. The array keys are the field names, and the array values are the corresponding object property names or PHP callables returning the field values.

toArray() public method

Converts the model into an array.

This method will first identify which fields to be included in the resulting array by calling resolveFields(). It will then turn the model into an array with these fields. If `$recursive` is true, any embedded objects will also be converted into arrays. When embedded objects are yii\base\Arrayable, their respective nested fields will be extracted and passed to toArray().

If the model implements the yii\web\Linkable interface, the resulting array will also have a `_link` element which refers to a list of links as specified by the interface.

public array toArray ( array $fields = [], array $expand = [], $recursive = true )
$fields | array | The fields being requested. If empty or if it contains '*', all fields as specified by fields() will be returned. Fields can be nested, separated with dots (.). e.g.: item.field.sub-field `$recursive` must be true for nested fields to be extracted. If `$recursive` is false, only the root fields will be extracted.
$expand | array | The additional fields being requested for exporting. Only fields declared in extraFields() will be considered. Expand can also be nested, separated with dots (.). e.g.: item.expand1.expand2 `$recursive` must be true for nested expands to be extracted. If `$recursive` is false, only the root expands will be extracted.
$recursive | boolean | Whether to recursively return array representation of embedded objects.
return | array | The array representation of the object