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Python Abstract base class

Summarize in 10 paragraphs. MUST include a SPECIFIC URL link to the Python Documentation. Give 8 Python code examples, 1 for plain ordinary Python, 1 for how it applies to Django, 1 for Flask, 1 for how it can be used in the AWS SDK for Python (Boto3), 1 for AWS Cloud Development Kit (AWS CDK), 1 for Azure SDK for Python, 1 for GCP Python Cloud Client Libraries, 1 for Pulumi for Infrastructure as Code. Put a section heading for each paragraph. In the final paragraphs, compare to equivalent features in C Sharp, JavaScript, C Language, Swift. You MUST put double square brackets around each computer buzzword or jargon or technical words. Answer in MediaWiki syntax.

Here's a comprehensive overview of Python's Abstract Base Classes (ABCs), including examples across various frameworks and comparisons with similar features in other programming languages, formatted in MediaWiki syntax.

Python's abstract base classes (ABCs) are a feature of the Python Standard Library that provides a way to define abstract classes and abstract methods. Abstract classes are classes that cannot be instantiated on their own but can be subclassed. Their primary purpose is to define a common API for a set of subclasses. ABCs use the module named `abc`. Abstract methods defined in an ABC must be overridden in the subclass before it can be instantiated. This mechanism enforces a contract for subclasses, ensuring that they implement specific methods from the base class. You can find more information on ABCs in the Python Documentation: s://docs.python.org/3/library/abc.html(https://docs.python.org/3/library/abc.html).

```python from abc import ABC, abstractmethod

class Shape(ABC):

   @abstractmethod
   def area(self):
       pass

class Circle(Shape):

   def __init__(self, radius):
       self.radius = radius

   def area(self):
       return 3.14 * self.radius ** 2

In Django, abstract base classes are often used in models to define common fields that can be inherited by other models: ```python from django.db import models

class BaseMeta(ABC):

   created_at = models.DateTimeField(auto_now_add=True)
   updated_at = models.DateTimeField(auto_now=True)

   class Meta:
       abstract = True

class User(BaseMeta):

   name = models.CharField(max_length=100)

Flask does not directly utilize ABCs in its core framework, but they can be useful for structuring larger applications or extensions: ```python from flask import Flask from abc import ABC, abstractmethod

class ServiceProvider(ABC):

   @abstractmethod
   def register(self, app: Flask):
       pass

class DatabaseService(ServiceProvider):

   def register(self, app: Flask):
       app.config['DATABASE_URI'] = 'sqlite:///example.db'

Using ABCs with Boto3 can help define a consistent interface for interacting with different AWS services: ```python import boto3 from abc import ABC, abstractmethod

class CloudStorage(ABC):

   @abstractmethod
   def upload_file(self, file_name, bucket):
       pass

class S3Storage(CloudStorage):

   def upload_file(self, file_name, bucket):
       s3 = boto3.client('s3')
       s3.upload_file(file_name, bucket, file_name)

Abstract classes in the AWS CDK can define a standard interface for cloud infrastructure components: ```python from aws_cdk import core from abc import ABC, abstractmethod

class InfrastructureComponent(ABC):

   @abstractmethod
   def define_resources(self, scope: core.Construct):

       pass

class MyS3Bucket(InfrastructureComponent):

   def define_resources(self, scope: core.Construct):
       core.s3.Bucket(scope, "MyBucket")

For Azure services, abstract classes can encapsulate common patterns for managing resources: ```python from azure.storage.blob import BlobServiceClient from abc import ABC, abstractmethod

class AzureStorage(ABC):

   @abstractmethod
   def upload_blob(self, container_name, blob_name, data):
       pass

class BlobStorage(AzureStorage):

   def upload_blob(self, container_name, blob_name, data):
       blob_service_client = BlobServiceClient.from_connection_string("YourConnectionString")
       blob_client = blob_service_client.get_blob_client(container=container_name, blob=blob_name)
       blob_client.upload_blob(data)

Similarly, in Google Cloud Platform services, abstract classes can be used to define common interfaces for resource management: ```python from google.cloud import storage from abc import ABC, abstractmethod

class CloudStorage(ABC):

   @abstractmethod
   def upload_file(self, bucket_name, source_file_name, destination_blob_name):
       pass

class GCPStorage(CloudStorage):

   def upload_file(self, bucket_name, source_file_name, destination_blob_name):
       storage_client = storage.Client()
       bucket = storage_client.bucket(bucket_name)
       blob = bucket.blob(destination_blob_name)
       blob.upload_from_filename(source_file_name)

Pulumi leverages programming languages for infrastructure as code, where abstract classes can standardize infrastructure component definitions: ```python import pulumi from abc import ABC, abstractmethod

class CloudResource(ABC):

   @abstractmethod
   def create_resources(self):
       pass

class MyNetwork(CloudResource):

   def create_resources(self):
       # Pulumi code to define network resources
       pass

1. **C Sharp**: In C#, abstract classes and methods are part of the language syntax, using the `abstract` keyword. Similar to Python, these classes cannot be instantiated and require subclasses to implement the abstract methods. 2. **JavaScript**: JavaScript does not have built-in support for abstract classes in its syntax. Instead, patterns like function throwing or prototypes are used to simulate abstract classes and methods. 3. **C Language**: C does not support abstract classes directly due to its procedural nature. However, similar behavior can be mimicked using function pointers in structs to achieve polymorphism. 4. **Swift**: Swift uses protocols to define a blueprint of methods, properties, and other requirements. Protocols are similar to interfaces in other languages and can achieve similar outcomes to abstract classes by requiring conforming types to implement specific methods or properties.

By integrating abstract base classes into your Python code, you can ensure a consistent implementation across different frameworks and services, leveraging the power of object-oriented programming to create more maintainable, scalable, and reliable applications.

Python Abstract base class

Use 1 paragraph each to compare Python with its equivalent is used in 1. Java, 2. C++20 3. TypeScript, 4. PowerShell, 5. Golang, 6. Rust. Include URL links to each Language Documentation. Be sure to include code examples for each language.

In the realm of software development, abstract base classes (ABCs) play a crucial role in designing a clear, maintainable structure for applications. While Python offers a direct way to create ABCs using its `abc` module, other programming languages have their unique approaches to abstraction and polymorphism.

1. **Java**: In Java, abstract classes and interfaces are the primary means to achieve abstraction. Abstract classes in Java can contain both abstract methods (without an implementation) and concrete methods (with an implementation). Interfaces can be thought of as purely abstract classes. Java's approach to abstract classes is more integrated into its type system compared to Python's dynamic nature. Documentation: [Java Abstract Classes and Methods](https://docs.oracle.com/javase/tutorial/java/IandI/abstract.html). ```java abstract class Animal {

 abstract void makeSound();

 void makeSound() {
   System.out.println("Bark");
 }

2. **C++20**: C++ uses pure virtual functions within classes to create abstract classes, known as interfaces in other languages. Unlike Python, where you decorate methods with `@abstractmethod`, C++ denotes abstract methods by setting them to 0 in their declaration. C++20 enhances this model with concepts and modules, providing a more sophisticated way of defining interfaces. Documentation: [C++ Abstract Classes](https://en.cppreference.com/w/cpp/language/abstract_class). ```cpp class Animal { public:

 virtual void makeSound() = 0; // Pure virtual function

 void makeSound() override {
   std::cout << "Bark\n";
 }

3. **TypeScript**: TypeScript, a superset of JavaScript, introduces static typing and interfaces to the dynamically typed world of JavaScript. Interfaces in TypeScript are a powerful way to define contracts within your code but do not compile to JavaScript. They are used by the TypeScript compiler for type checking. This is a contrast to Python’s runtime checks for abstract methods. Documentation: [TypeScript Interfaces](https://www.typescriptlang.org/docs/handbook/interfaces.html). ```typescript interface Animal {

 makeSound(): void;

 makeSound() {
   console.log("Bark");
 }

4. **PowerShell**: PowerShell, primarily a scripting language for system administration, does not have a direct equivalent to abstract classes. It focuses on cmdlets and scripts for managing systems rather than object-oriented programming constructs. However, you can simulate some aspects of polymorphism through advanced functions and custom classes introduced in PowerShell 5.0. Documentation: [PowerShell Classes](https://docs.microsoft.com/en-us/powershell/scripting/learn/ps101/09-classes-and-objects). ```powershell class Animal {

 [void]MakeSound() {
   throw "Not implemented"
 }

 [void]MakeSound() {
   Write-Output "Bark"
 }

5. **Golang**: Go does not have classes or inheritances in the traditional sense. Instead, it uses interfaces to achieve polymorphism. An interface in Go is a set of method signatures. A type implements an interface by implementing its methods. There is no explicit declaration of intent. This approach is minimalistic compared to Python's explicit declaration of abstract methods and classes. Documentation: [Go Interfaces](https://golang.org/doc/effective_go#interfaces). ```go type Animal interface {

 MakeSound()

 fmt.Println("Bark")

6. **Rust**: Rust uses traits to specify shared behavior in an abstract way. Similar to interfaces in other languages, traits define a set of methods that types must implement. Rust’s approach is more about ensuring compile-time safety and avoiding runtime errors, contrasting with Python’s runtime checks. Traits can be used to implement polymorphism and ensure that types adhere to a specific interface. Documentation: [Rust Traits](https://doc.rust-lang.org/book/ch10-02-traits.html). ```rust trait Animal {

 fn make_sound(&self);

 fn make_sound(&self) {
   println!("Bark");
 }

Each language adopts a different strategy for abstract classes or their equivalents, tailored to its type system, programming paradigms, and use cases. From Java's and C++'s classical approach to TypeScript's static type checking and Rust's compile-time safety with traits, the concept of abstraction and polymorphism is a fundamental part of modern programming, allowing for more flexible, reusable, and maintainable code.

Python abstract base class - Abstract base classes complement Python duck-typing by providing a way to define Python interfaces when other techniques like Python hasattr() would be clumsy or subtly wrong (for example with Python magic methods). ABCs introduce Python virtual subclasses, which are Python classes that don’t inherit from a class but are still recognized by Python isinstance() and Python issubclass(); see the Python abc module documentation. Python comes with many Python built-in ABCs for Python data structures (in the Python collections.abc module), Python numbers (in the Python numbers module), Python streams (in the Python io module), Python import finders and Python loaders (in the Python importlib.abc module). You can create your own Python ABCs with the Python abc module.

Fair Use Source: https://docs.python.org/3/glossary.html

• Python abstract base class - Python Abstract base classes complement Python duck-typing by providing a way to define Python interfaces when other techniques like Python hasattr() would be clumsy or subtly wrong (for example with Python magic methods). Python ABCs introduce Python virtual subclasses, which are Python classes that don’t Python inherit from a Python class but are still recognized by Python isinstance() and Python issubclass(); see the Python abc module Python documentation. Python comes with many Python built-in ABCs for Python data structures (in the Python collections.abc module), Python numbers (in the Python numbers module), Python streams (in the Python io module), Python import finders and Python loaders (in the Python importlib.abc module). You can create your own Python ABCs with the Python abc module.

Snippet from Wikipedia: Class (computer programming)

In object-oriented programming, a class is an extensible program-code-template for creating objects, providing initial values for state (member variables) and implementations of behavior (member functions or methods).

When an object is created by a constructor of the class, the resulting object is called an instance of the class, and the member variables specific to the object are called instance variables, to contrast with the class variables shared across the class.

In certain languages, classes are, as a matter of fact, only a compile time feature (new classes cannot be declared at runtime), while in other languages classes are first-class citizens, and are generally themselves objects (typically of type Class or similar). In these languages, a class that creates classes within itself is called a metaclass.

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Fair Use Sources:

• Official Python Glossary (POG 2024)
• FlntPy Lingo 2022