Learning Python电子书

Learning Python

Table of Contents

Learning Python

Credits

About the Author

Acknowledgements

About the Reviewers

www.PacktPub.com

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Why subscribe?

Free access for Packt account holders

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Errata

Piracy

Questions

1. Introduction and First Steps – Take a Deep Breath

A proper introduction

Enter the Python

About Python

Portability

Coherence

Developer productivity

An extensive library

Software quality

Software integration

Satisfaction and enjoyment

What are the drawbacks?

Who is using Python today?

Setting up the environment

Python 2 versus Python 3 – the great debate

Installing Python

Setting up the Python interpreter

About virtualenv

Your first virtual environment

Your friend, the console

How you can run a Python program

Running Python scripts

Running the Python interactive shell

Running Python as a service

Running Python as a GUI application

How is Python code organized

How do we use modules and packages

Python's execution model

Names and namespaces

Scopes

Object and classes

Guidelines on how to write good code

The Python culture

A note on the IDEs

Summary

2. Built-in Data Types

Everything is an object

Mutable or immutable? That is the question

Numbers

Integers

Booleans

Reals

Complex numbers

Fractions and decimals

Immutable sequences

Strings and bytes

Encoding and decoding strings

Indexing and slicing strings

Tuples

Mutable sequences

Lists

Byte arrays

Set types

Mapping types – dictionaries

The collections module

Named tuples

Defaultdict

ChainMap

Final considerations

Small values caching

How to choose data structures

About indexing and slicing

About the names

Summary

3. Iterating and Making Decisions

Conditional programming

A specialized else: elif

The ternary operator

Looping

The for loop

Iterating over a range

Iterating over a sequence

Iterators and iterables

Iterating over multiple sequences

The while loop

The break and continue statements

A special else clause

Putting this all together

Example 1 – a prime generator

Example 2 – applying discounts

A quick peek at the itertools module

Infinite iterators

Iterators terminating on the shortest input sequence

Combinatoric generators

Summary

4. Functions, the Building Blocks of Code

Why use functions?

Reduce code duplication

Splitting a complex task

Hide implementation details

Improve readability

Improve traceability

Scopes and name resolution

The global and nonlocal statements

Input parameters

Argument passing

Assignment to argument names don't affect the caller

Changing a mutable affects the caller

How to specify input parameters

Positional arguments

Keyword arguments and default values

Variable positional arguments

Variable keyword arguments

Keyword-only arguments

Combining input parameters

Avoid the trap! Mutable defaults

Return values

Returning multiple values

A few useful tips

Recursive functions

Anonymous functions

Function attributes

Built-in functions

One final example

Documenting your code

Importing objects

Relative imports

Summary

5. Saving Time and Memory

map, zip, and filter

map

zip

filter

Comprehensions

Nested comprehensions

Filtering a comprehension

dict comprehensions

set comprehensions

Generators

Generator functions

Going beyond next

The yield from expression

Generator expressions

Some performance considerations

Don't overdo comprehensions and generators

Name localization

Generation behavior in built-ins

One last example

Summary

6. Advanced Concepts – OOP, Decorators, and Iterators

Decorators

A decorator factory

Object-oriented programming

The simplest Python class

Class and object namespaces

Attribute shadowing

I, me, and myself – using the self variable

Initializing an instance

OOP is about code reuse

Inheritance and composition

Accessing a base class

Multiple inheritance

Method resolution order

Static and class methods

Static methods

Class methods

Private methods and name mangling

The property decorator

Operator overloading

Polymorphism – a brief overview

Writing a custom iterator

Summary

7. Testing, Profiling, and Dealing with Exceptions

Testing your application

The anatomy of a test

Testing guidelines

Unit testing

Writing a unit test

Mock objects and patching

Assertions

A classic unit test example

Making a test fail

Interface testing

Comparing tests with and without mocks

Boundaries and granularity

A more interesting example

Test-driven development

Exceptions

Profiling Python

When to profile?

Summary

8. The Edges – GUIs and Scripts

First approach – scripting

The imports

Parsing arguments

The business logic

Second approach – a GUI application

The imports

The layout logic

The business logic

Fetching the web page

Saving the images

Alerting the user

How to improve the application?

Where do we go from here?

The tkinter.tix module

The turtle module

wxPython, PyQt, and PyGTK

The principle of least astonishment

Threading considerations

Summary

9. Data Science

IPython and Jupyter notebook

Dealing with data

Setting up the notebook

Preparing the data

Cleaning the data

Creating the DataFrame

Unpacking the campaign name

Unpacking the user data

Cleaning everything up

Saving the DataFrame to a file

Visualizing the results

Where do we go from here?

Summary

10. Web Development Done Right

What is the Web?

How does the Web work?

The Django web framework

Django design philosophy

The model layer

The view layer

The template layer

The Django URL dispatcher

Regular expressions

A regex website

Setting up Django

Starting the project

Creating users

Adding the Entry model

Customizing the admin panel

Creating the form

Writing the views

The home view

The entry list view

The form view

Tying up URLs and views

Writing the templates

The future of web development

Writing a Flask view

Building a JSON quote server in Falcon

Summary

11. Debugging and Troubleshooting

Debugging techniques

Debugging with print

Debugging with a custom function

Inspecting the traceback

Using the Python debugger

Inspecting log files

Other techniques

Profiling

Assertions

Where to find information

Troubleshooting guidelines

Using console editors

Where to inspect

Using tests to debug

Monitoring

Summary

12. Summing Up – A Complete Example

The challenge

Our implementation

Implementing the Django interface

The setup

The model layer

A simple form

The view layer

Imports and home view

Listing all records

Creating records

Updating records

Deleting records

Setting up the URLs

The template layer

Home and footer templates

Listing all records

Creating and editing records

Talking to the API

Deleting records

Implementing the Falcon API

The main application

Writing the helpers

Coding the password validator

Coding the password generator

Writing the handlers

Coding the password validator handler

Coding the password generator handler

Running the API

Testing the API

Testing the helpers

Testing the handlers

Where do you go from here?

Summary

A word of farewell

Index