We'll look at the three canonical special methods for attribute access: __getattr__()
, __setattr__()
, and __delattr__()
. Additionally, we'll acknowledge the __dir__()
method to reveal attribute names. We'll defer __getattribute__()
to the next section.
The default behavior shown in the first section is as follows:
The
__getattr__()
method will do two things. Firstly, if an attribute already has a value,__getattr__()
is not used; the attribute value is simply returned. Secondly, if the attribute does not have a value, then__getattr__()
is given a chance to return a meaningful value. If there is no attribute, it must raise anAttributeError
exception.
The __getattr__()
method function is only one step in a larger process; it is only used if the attribute is otherwise unknown. If the attribute is...