Arman

$form = new ContactForm();
$form->tel = $user->tel;

$id = Yii::$app->user->identity->id;
$user = ContactForm::find()->where(['user_id' => $id])->one();
$form = new ContactForm($user);
if ($form->load(Yii::$app->request->post()) && $form->validate() && $form->save()) {
    return $this->refresh();
}else{
    return $this->render('profile', compact('form', 'user'));
}

$var1 = isset($var2) && $var2 ? $var2 : $var3; // до 7.0
$var1 = $var2 ?? $var3; // c 7.0

var size = 7;
var i = 0; // 1, 2, 3

var limit = (i - 1) * 7;
var offset = limit + size;

class A {
    private $vаlue = 333;
//...