How do I understand variable references?

public function search($params){    $query = Post::find();    $dataProvider = new ActiveDataProvider([        # @1        'query' => $query,    ]);    # @2    $query->andFilterWhere(['id' => $this->id]);    $query->andFilterWhere(['like', 'title', $this->title])          ->andFilterWhere(['like', 'creation_date', $this->creation_date]);    # @3    return $dataProvider;}

At @1, $query this variable is assigned to the $dataProvider query property;
In the @2, $query have added some query conditions;

May I ask, at the @3 $dataProvider query property, how do you have the conditions that $query add to the @2?

Code Source

Reply content:

public function search($params){    $query = Post::find();    $dataProvider = new ActiveDataProvider([        # @1        'query' => $query,    ]);    # @2    $query->andFilterWhere(['id' => $this->id]);    $query->andFilterWhere(['like', 'title', $this->title])          ->andFilterWhere(['like', 'creation_date', $this->creation_date]);    # @3    return $dataProvider;}

At @1, $query this variable is assigned to the $dataProvider query property;
In the @2, $query have added some query conditions;

May I ask, at the @3 $dataProvider query property, how do you have the conditions that $query add to the @2?

Code Source

See http://php.net/manual/en/language.oop5.references.php

In PhP5, an object variable has no longer saved the value of the entire object. Just save an identifier to access the real object content.

class A{    public $foo = 1;}$a = new A;$b = $a;echo $b->foo; # 1$a->foo = 2;echo $b->foo; # 2

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