The use of session and cookie in yii2.0 framework

We use the session and Cookie in the south of the development project, so there are rules in yii.
The following cases:

Session use
FunctionactionS1 () {
echo $this->id. "
";
echo $this->action->id. "
";
Set session, set by session component
Yii::app ()->session[' username '] = "Zhangsan";
Yii::app ()->session[' useraddr '] = "Beijing";
echo "Make session Success";
}

FunctionactionS2 () {
Use session
Echo Yii::app ()->session[' username '], "
";
Echo Yii::app ()->session[' useraddr '];
echo "Use session success";
}

FunctionactionS3 () {
Delete a session
Unset (Yii::app ()->session[' useraddr ']);

Delete all session
Yii::app ()->session->clear (); Delete Session variable
Yii::app ()->session->destroy (); Delete session information for the server
}

Cookies are used in YII framework
FunctionactionC1 () {
Set cookies
$ck = new Chttpcookie (' hobby ', ' basketball, football ');
$ck-expire = time () +3600;
Put the $ck object inside the cookie component
Yii::app ()->request->cookies[' hobby '] = $ck;

$ck 2 = new Chttpcookie (' Sex ', ' nan ');
$ck 2-expire = time () +3600;
Put the $ck object inside the cookie component
Yii::app ()->request->cookies[' sex ' = $ck 2;

echo "Cookie make success";
}
FunctionactionC2 () {
accessing cookies
Echo Yii::app ()->request->cookies[' hobby '], "
";
Echo Yii::app ()->request->cookies[' sex ';
}
FunctionactionC3 () {
Delete Cookies
Unset (Yii::app ()->request->cookies[' sex ');
}

The use of session and cookie in yii2.0 framework