How can an object be placed in an array?

Can an Object be put into an array? there is a static class method to return an Object using print_r to print for example: User & nbsp; Object & nbsp; (& nbsp; [UserID: private] & nbsp; = & gt; & nbsp; 1829 & nbsp; [can an object of UserInfoA be placed in an array?
There is a static method of the class that returns an object using print_r to print such:
User Object ([UserID: private] ==> 1829 [UserInfoArr: private] => Array ([UserName] => dong [UserPasswd] => 9d10b7eae72c5f1bb0b4fc1a68a34032 [Description] => AB [IsAuthEmail] => 0 [IsDelete] => 0 ))
Now I want to retrieve the UserName of the array in the object, but none of them can be successful. how can I read the value of the array in the object? Or can the object not have arrays? is this method (the object has arrays) incorrect?
------ Solution --------------------
You must first change the UserInfoArr attribute to a public attribute, rather than a private attribute that disables external access.