# 类和对象
class Person:
def __init__(self, name, age):
self.name = name
self.age = age

def greet(self):
return f”Hello, my name is {self.name}”

def get_age(self):
return self.age

# 创建对象
person = Person(“John”, 30)
print(person.greet())
print(person.get_age())

# 继承
class Student(Person):
def __init__(self, name, age, student_id):
super().__init__(name, age)
self.student_id = student_id

def get_student_id(self):
return self.student_id

# 创建学生对象
student = Student(“Alice”, 20, “12345”)
print(student.greet())
print(student.get_student_id())

# 创建模块 (mymodule.py)
# def greet(name):
# return f”Hello, {name}!”

# 导入模块
import mymodule
print(mymodule.greet(“John”))

# 从模块导入特定函数
from mymodule import greet
print(greet(“Alice”))

# 导入所有函数
from mymodule import *

# 创建包
# 创建一个目录，包含__init__.py文件
# mypackage/
# __init__.py
# module1.py
# module2.py

# 导入包
import mypackage.module1
print(mypackage.module1.function1())

# 写入文件
with open(“example.txt”, “w”) as f:
f.write(“Hello, Python!\n”)
f.write(“This is a test file.\n”)

# 读取文件
with open(“example.txt”, “r”) as f:
content = f.read()
print(content)

# 逐行读取
with open(“example.txt”, “r”) as f:
for line in f:
print(line.strip())

# 追加文件
with open(“example.txt”, “a”) as f:
f.write(“This is an appended line.\n”)

try:
# 可能抛出异常的代码
result = 10 / 0
except ZeroDivisionError:
# 捕获特定异常
print(“Error: Division by zero”)
except Exception as e:
# 捕获所有异常
print(f”Error: {e}”)
finally:
# 无论是否发生异常都会执行的代码
print(“Execution completed”)

# 自定义异常
class CustomError(Exception):
pass

try:
raise CustomError(“This is a custom error”)
except CustomError as e:
print(f”Custom error: {e}”)

# 列表推导式
numbers = [1, 2, 3, 4, 5]
squares = [x**2 for x in numbers]
print(squares) # [1, 4, 9, 16, 25]

# 生成器
def fibonacci(n):
a, b = 0, 1
for _ in range(n):
yield a
a, b = b, a + b

for num in fibonacci(10):
print(num)

# 装饰器
def log_function(func):
def wrapper(*args, **kwargs):
print(f”Calling function: {func.__name__}”)
result = func(*args, **kwargs)
print(f”Function {func.__name__} completed”)
return result
return wrapper

@log_function
def add(a, b):
return a + b

print(add(1, 2))

# 安装第三方库
# pip3 install requests numpy pandas matplotlib

# 使用requests库
import requests
response = requests.get(“https://api.github.com”)
print(response.status_code)
print(response.json())

# 使用numpy库
import numpy as np
arr = np.array([1, 2, 3, 4, 5])
print(arr.mean())
print(arr.max())

# 使用pandas库
import pandas as pd
df = pd.DataFrame({
“name”: [“John”, “Alice”, “Bob”],
“age”: [30, 20, 25]
})
print(df)

# 使用matplotlib库
import matplotlib.pyplot as plt
x = [1, 2, 3, 4, 5]
y = [2, 4, 6, 8, 10]
plt.plot(x, y)
plt.xlabel(“X-axis”)
plt.ylabel(“Y-axis”)
plt.title(“Line Plot”)
plt.savefig(“plot.png”)

# 代码风格示例（PEP 8）
# 使用4个空格缩进
# 每行不超过79个字符
# 函数和类之间空两行
# 方法之间空一行

# 性能优化
# 使用生成器节省内存
def generate_numbers(n):
for i in range(n):
yield i

# 使用字典或集合进行快速查找
names = set([“John”, “Alice”, “Bob”])
if “John” in names: # O(1)操作
print(“John is in the set”)

# 错误处理最佳实践
def divide(a, b):
if b == 0:
raise ValueError(“Division by zero”)
return a / b

try:
result = divide(10, 0)
except ValueError as e:
print(f”Error: {e}”)