Python 3.6.9 : My colab tutorials - part 011.

The purpose of this tutorial is to use the google TPU device together with Keras.

You need to set from the Edit menu and set for the notebook the device called TPU.

You can find the source code on my GitHub account here.

Python 3.9.1 : ABC - Abstract Base Classes - part 001.

Abstract classes are classes that contain one or more abstract methods.

By default, Python does not provide abstract classes.

Python comes with a module that provides the base for defining Abstract Base Classes (named ABC).

An abstract class can be considered as a blueprint for other classes.

By defining an abstract base class, you can define a common API for a set of subclasses.

A class that is derived from an abstract class cannot be instantiated unless all of its abstract methods are overridden.

[mythcat@desk ~]$ python3.9
Python 3.9.5 (default, May  4 2021, 00:00:00) 
[GCC 10.3.1 20210422 (Red Hat 10.3.1-1)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from abc import ABC
>>> class Test_ABC(ABC):
...     pass
... 
>>> Test_ABC.register(tuple)

>>> assert issubclass(tuple,Test_ABC)
>>> assert isinstance((), Test_ABC)
>>> class Foo:
...     def __getitem__(self, index):
...         ...
...     def __len__(self):
...         ...
...     def get_iterator(self):
...         return iter(self)
... 
>>> Test_ABC.register(Foo)
...

Let's see an example:

from abc import ABC, abstractmethod
 
class Vehicle(ABC):
    @abstractmethod
    def action(self):
        pass

class Air(Vehicle):
    # overriding abstract method
    def action(self):
        print("this flies in the air")
 
class Ground(Vehicle):
    # overriding abstract method
    def action(self):
        print("this running on the field")

class Civil(Ground):
    def action(self):
        print("Civil class - running on the field")

# Can't instantiate abstract class with abstract method action, don't use it
# abc = Vehicle()

abc = Air()
abc.action()

abc = Ground()
abc.action()

abc = Civil()
abc.action()

print( issubclass(Civil, Vehicle))
print( isinstance(Civil(), Vehicle))

This is the result:

[mythcat@desk PythonProjects]$ python3.9 ABC_001.py 
this flies in the air
this running on the field
Civil class - running on the field
True
True