重点摘要
1. Python基础：变量、字符串和数字
变量是具有名称的存储位置。
变量和数据类型。 Python提供了几种基本数据类型，包括字符串、整数和浮点数。变量是使用赋值运算符（=）创建的，可以存储这些数据类型中的任何一种。字符串用引号括起来，并支持各种操作，如连接和重复。
字符串操作。 Python提供了内置函数和方法来处理字符串：
- len()：返回字符串的长度
- upper()和lower()：将字符串转换为大写或小写
- format()：允许字符串插值
- 索引和切片：访问单个字符或子字符串
数值操作。 Python支持基本的算术运算（+，-，*，/）以及更高级的运算，如指数运算（**）和取模运算（%）。该语言还提供了用于类型转换（int()，float()，str()）和数学运算（max()，min()）的内置函数。
2. 控制流：布尔值、条件语句和函数
函数允许你编写一次Python代码块并多次使用。
布尔逻辑。 Python使用True和False作为布尔值。比较运算符（==，!=，>，<，>=，<=）和逻辑运算符（and，or，not）用于创建布尔表达式。
条件语句。 控制流是通过if，elif和else语句管理的：
- if 条件:
代码块
- elif 另一个条件:
代码块
- else:
代码块
函数。 函数是使用def关键字定义的，后跟函数名称和参数。它们可以接受参数，执行操作并返回值。函数促进代码的重用和组织。
3. 数据结构：列表、字典和元组
列表是一种包含有序项目集合的数据类型。
列表。 列表是可变的、有序的项目集合。它们是使用方括号[]创建的，并支持各种操作：
- 索引和切片
- append()，extend()和insert()用于添加项目
- remove()和pop()用于删除项目
- sort()用于排序项目
字典。 字典是无序的键值对集合。它们是使用花括号{}和冒号分隔键和值创建的。字典提供快速查找，非常适合存储结构化数据。
元组。 元组是不可变的、有序的项目集合。它们是使用圆括号()创建的，通常用于固定的数据集。虽然它们的内容在创建后不能更改，但元组可以解包到多个变量中。
4. 文件处理：读取、写入和模式
要打开文件，请使用内置的open()函数。
打开文件。 open()函数用于打开文件，有多种模式可用：
- 'r'：读取（默认）
- 'w'：写入（覆盖现有内容）
- 'a'：追加
- 'b'：二进制模式
读取和写入。 文件可以使用read()，readline()或readlines()方法读取。写入是使用write()方法完成的。建议使用with语句在使用后自动关闭文件。
文件模式和错误处理。 不同的文件模式允许进行各种操作，如读取、写入或追加。在处理文件时，使用try/except块捕获异常（如FileNotFoundError）来处理潜在的错误非常重要。
5. 模块化编程：导入和创建模块
Python模块是具有.py扩展名的文件，可以实现一组属性（变量）、方法（函数）和类（类型）。
导入模块。 模块可以使用import语句导入。可以使用from module import function导入特定的函数或属性。这允许代码重用和组织。
创建模块。 自定义模块可以通过将Python代码保存在.py文件中创建。这些模块可以在其他Python脚本中导入和使用。__name__变量可以用来确定模块是直接运行还是被导入。
模块搜索路径。 Python使用搜索路径来查找模块。可以使用PYTHONPATH环境变量或通过在代码中操作sys.path来修改此路径。
6. 错误处理：异常和Try/Except块
异常通常表示程序中出现了错误或意外情况。
异常类型。 Python有许多内置的异常类型，如ValueError，TypeError和FileNotFoundError。这些有助于识别代码中的特定问题。
Try/except块。 异常可以使用try/except块捕获和处理：
try:
# 可能引发异常的代码
except ExceptionType:
# 处理异常的代码
自定义异常。 程序员可以通过继承内置的Exception类来创建自定义异常类。这允许在复杂应用程序中进行更具体的错误处理。
7. Python标准库：内置模块和函数
Python附带了一个大型的模块库，你可以利用它们。
常见的标准库模块：
- time：用于时间相关的函数
- sys：用于系统特定的参数和函数
- os：用于操作系统接口
- json：用于JSON编码和解码
- csv：用于读取和写入CSV文件
- random：用于生成随机数
内置函数。 Python提供了许多始终可用的内置函数：
- print()：用于输出到控制台
- input()：用于用户输入
- len()：用于获取序列的长度
- range()：用于生成数字序列
- type()：用于确定对象的类型
探索模块。 dir()函数可用于探索模块的内容，显示可用的函数和属性。help()函数提供模块、函数和对象的详细文档。
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FAQ
What's "Python Programming for Beginners" about?
- Introduction to Python: The book is designed to introduce beginners to the Python programming language and computer programming concepts.
- Step-by-step Guidance: It provides a systematic approach to learning Python, assuming no prior knowledge of programming.
- Practical Examples: The book includes numerous examples and exercises to reinforce learning and provide hands-on experience.
- Comprehensive Coverage: Topics range from basic concepts like variables and strings to more advanced topics like file handling and modules.
Why should I read "Python Programming for Beginners"?
- Beginner-Friendly: It's tailored for those new to programming, making it accessible and easy to understand.
- Practical Focus: The book emphasizes practical skills, allowing readers to apply what they learn immediately.
- Comprehensive Resource: It covers a wide range of topics, providing a solid foundation in Python programming.
- Free Resources: Readers can access additional resources and examples online to enhance their learning experience.
What are the key takeaways of "Python Programming for Beginners"?
- Python Environment Setup: Learn how to install and configure Python on different operating systems.
- Core Python Concepts: Understand variables, strings, numbers, conditionals, loops, functions, and data structures like lists, dictionaries, and tuples.
- File Handling: Gain skills in reading from and writing to files, an essential part of many programming tasks.
- Modules and Libraries: Discover how to use Python's standard library and create your own modules for code reuse.
How does Jason Cannon suggest setting up the Python environment?
- Choosing Python Version: The author recommends using Python 3 for new projects, as Python 2 is considered legacy.
- Installation Instructions: Detailed steps are provided for installing Python on Windows, Mac, and Linux systems.
- Using IDLE: The book explains how to use IDLE, Python's Integrated Development Environment, for writing and running Python code.
- Command Line Usage: Instructions are given for running Python programs from the command line on different operating systems.
What are the basic concepts of Python covered in the book?
- Variables and Strings: Learn how to create and manipulate variables and strings, including string methods and formatting.
- Numbers and Math: Understand numeric operations, type conversion, and the use of comments in code.
- Booleans and Conditionals: Explore boolean logic, comparators, and conditional statements like if, elif, and else.
- Functions: Discover how to define and use functions, including parameters, return values, and docstrings.
How does the book explain data structures like lists and dictionaries?
- Lists: Learn how to create, modify, and access lists, including list methods like append, extend, and sort.
- Dictionaries: Understand how to work with key-value pairs, adding, removing, and accessing items in a dictionary.
- Tuples: Explore the concept of immutable lists and how to use tuple assignment for multiple variables.
- Nesting and Looping: The book covers nesting data structures and looping through lists and dictionaries.
What file handling techniques are taught in "Python Programming for Beginners"?
- Reading Files: Learn how to open and read files using Python's built-in functions and methods.
- Writing Files: Understand how to write data to files, including appending and creating new files.
- File Modes: The book explains different file modes like read, write, append, and binary modes.
- Exception Handling: Discover how to handle exceptions when working with files to prevent program crashes.
How does Jason Cannon introduce modules and the Python Standard Library?
- Importing Modules: Learn how to import and use modules in Python, including specific functions and attributes.
- Standard Library: The book highlights useful modules in Python's standard library, such as time and sys.
- Creating Modules: Instructions are provided for creating your own modules to organize and reuse code.
- Module Search Path: Understand how Python searches for modules and how to modify the search path if needed.
What are some practical exercises included in the book?
- To-Do List Program: Create a program that captures and displays a user's to-do list using lists and loops.
- Word Game: Develop a fill-in-the-blank word game that uses user input and string formatting.
- Cost Calculator: Write a program to calculate the cost of cloud hosting, incorporating numeric operations and conditionals.
- Cat Say Program: Build a program that displays a cat "saying" user input, demonstrating string manipulation and functions.
What are the best quotes from "Python Programming for Beginners" and what do they mean?
- "Don't Repeat Yourself (DRY):" This principle emphasizes writing reusable code to avoid redundancy and improve maintainability.
- "Everything in Python is an object:" Highlights Python's object-oriented nature, where even basic data types are treated as objects.
- "Errors should never pass silently:" Encourages handling exceptions explicitly to ensure robust and reliable code.
- "Readability counts:" Stresses the importance of writing clear and understandable code, a core philosophy of Python.
How does the book address common Python errors?
- Troubleshooting Guide: The book offers a guide to common Python errors and how to troubleshoot them effectively.
- Error Examples: Examples of typical coding mistakes are provided, along with explanations and solutions.
- Practice Exercises: Readers are encouraged to practice identifying and fixing errors through exercises and examples.
- Online Resources: Additional resources are available online to help readers further understand and resolve Python errors.
What additional resources does Jason Cannon provide for learning Python?
- Free Gifts: Readers can download a copy of "Common Python Errors" and a Python cheat sheet for quick reference.
- Online Courses: The author offers online video training courses for further learning and skill development.
- Other Books: Jason Cannon has authored other books on related topics, such as Linux and shell scripting, which can complement Python learning.
- Community Support: The book encourages joining online communities and forums for support and collaboration with other learners.
评论
《Python编程入门》获得了大多数正面评价，平均评分为3.90/5。读者们赞赏其清晰、简洁和对初学者的有效性。该书因其易于理解的解释、实用的例子和练习而受到好评。一些批评意见包括拼写错误、偶尔不工作的例子以及缺乏高级内容。尽管有些人认为其内容定价过高，但许多人认为这是学习Python基础的一个良好起点。该书特别推荐给绝对初学者，但对有经验的程序员可能用处不大。
