Ariel Ortiz - (Tutorial) Design Patterns in Python for the Untrained Eye

Design patterns are prepackaged solutions to common software design problems. We get two important benefits when using them. Firstly, we get a way to solve typical software development issues by using a proven solution. Secondly, we get a shared vocabulary that allows us to communicate more effectively with other software designers. Getting acquainted with design patterns is the next step to become a better object oriented programmer.

In this tutorial we'll answer some of the most important questions surrounding design patterns: What are they? How can we use them in our programs? When should we avoid them? We'll also have the opportunity to explore and play with the Python implementations of some of the classical design patterns made famous by the Gang of Four (Gamma, Helm, Johnson & Vlissides) while learning relevant design principles at the same time. Don't forget to bring your own laptop with your preferred Python 3 development environment.

https://us.pycon.org/2019/schedule/presentation/83/

Transcript

1. Design Patterns in Python for the Untrained Eye
2. bit.ly/2V819eq Material for the tutorial:
3. Ariel Ortiz Full time faculty member Tecnológico de Monterrey Mexico
4. What is a Pattern? 4
5. Patterns capture experiences in software development that have been proven to work again and again, and thus provide a solution to specific problems. They are not invented, they are discovered.
6. Categories by Abstraction Level ▪ Idioms ▪ Architectural Patterns ▪ Design Patterns
7. Relevance of Design Patterns ▪ Tried and tested solutions ▪ Common language
8. Limitations of Design Patterns ▪ Unjustified Use ▪ Kludges for a Weak Programming Language ▪ Inefficient Solutions
9. A Bit of History The Gang of Four GoF
10. 23 Design Patterns Classified Based on their Use ▪ Creational Pattern ▪ Structural Patterns ▪ Behavioral Patterns
11. Design Principles 11
12. 1. Separate out the things that change from those that stay the same Design Principles
13. 2. Program to an interface, not an implementation Design Principles
14. 3. Prefer composition over inheritance Design Principles
15. 4. Delegation Design Principles
16. Anatomy of a Design Pattern ▪ Intent ▪ Motivation ▪ Structure ▪ Implementation
17. Singleton Pattern 17
18. Singleton is a creational design pattern that lets you ensure that a class has only one instance, while providing a global access point to this instance.
20. Template Method Pattern 20
21. Template Method is a behavioral design pattern that defines the skeleton of an algorithm in the base class but lets derived classes override specific steps of the algorithm without changing its structure.
23. Adapter Pattern 23
24. Adapter is a structural design pattern that converts the interface of a class into another interface clients expect. Adapter lets classes work together that couldn’t otherwise because of incompatible interfaces.
26. Observer Pattern 26
27. Observer is a behavioral design pattern that defines a one-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
29. CONCLUSIONS 29
30. Thanks! ariel.ortiz.ramirez@gmail.com 30
31. Credits Special thanks to: ▪ Presentation template by SlidesCarnival ▪ Icons made by Freepik from Flaticon 31