Python进阶之路模块、包和异常处理详解

# math_utils.py
def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

# 导入整个模块
import math_utils

print(math_utils.add(2, 3))  # 输出：5

# 导入模块中的特定函数
from math_utils import subtract

print(subtract(5, 2))  # 输出：3

# 使用别名导入
import math_utils as mu

print(mu.add(4, 6))  # 输出：10

import math
import random

print(math.sqrt(16))  # 输出：4.0
print(random.randint(1, 10))  # 输出：1到10之间的随机整数

my_package/
    __init__.py
    math_utils.py
    string_utils.py

# 文件结构
my_package/
    __init__.py
    math_utils.py
    string_utils.py

# math_utils.py
def add(a, b):
    return a + b

# string_utils.py
def to_uppercase(s):
    return s.upper()

# 导入整个包中的模块
from my_package import math_utils, string_utils

print(math_utils.add(3, 4))  # 输出：7
print(string_utils.to_uppercase("hello"))  # 输出：HELLO

# 从模块中导入特定函数
from my_package.math_utils import add

print(add(5, 6))  # 输出：11

print(10 / 0)  # ZeroDivisionError: division by zero
print(undefined_variable)  # NameError: name 'undefined_variable' is not defined

try:
    print(10 / 0)
except ZeroDivisionError:
    print("Cannot divide by zero!")  # 输出：Cannot divide by zero!

try:
    print(undefined_variable)
except (ZeroDivisionError, NameError) as e:
    print(f"An error occurred: {e}")

try:
    result = 10 / 2
except ZeroDivisionError:
    print("Cannot divide by zero!")
else:
    print(f"Result is {result}")  # 输出：Result is 5.0
finally:
    print("Execution completed.")  # 输出：Execution completed.

class CustomError(Exception):
    pass

def check_positive(value):
    if value < 0:
        raise CustomError("Value must be positive!")

try:
    check_positive(-10)
except CustomError as e:
    print(e)  # 输出：Value must be positive!

calendar_app/
    __init__.py
    event_manager.py
    utils.py

class EventManager:
    def __init__(self):
        self.events = []

    def add_event(self, event):
        self.events.append(event)

    def list_events(self):
        return self.events

    def delete_event(self, event):
        if event in self.events:
            self.events.remove(event)
        else:
            raise ValueError("Event not found!")

def format_event(event):
    return f"Event: {event}"

from calendar_app.event_manager import EventManager
from calendar_app.utils import format_event

manager = EventManager()

# 添加事件
manager.add_event("Meeting at 10 AM")
manager.add_event("Lunch at 12 PM")

# 列出事件
events = manager.list_events()
for event in events:
    print(format_event(event))  # 格式化输出事件

# 删除事件
manager.delete_event("Lunch at 12 PM")
print(manager.list_events())  # 输出：['Meeting at 10 AM']