try:
    10 / 0  # 觸發(fā) ZeroDivisionError 異常，Python 會創(chuàng)建該異常的對象
except ZeroDivisionError as e:  # 將異常對象綁定到變量 e
    print(f"錯誤描述：{e}")  # 訪問異常對象的信息，輸出：division by zero
    print(f"異常類型：{type(e)}")  # 輸出：<class 'ZeroDivisionError'>

try:
    data = {"name": "張三"}
    print(data["age"])  # 可能觸發(fā) KeyError
    # 10 / 0  # 可能觸發(fā) ZeroDivisionError
except (KeyError, ZeroDivisionError) as e:
    # 通過 type(e) 區(qū)分異常類型，針對性處理
    if isinstance(e, KeyError):
        print(f"鍵不存在：{e}")
    else:
        print(f"除數(shù)為0：{e}")

# 大數(shù)據(jù)/數(shù)據(jù)分析領(lǐng)域的常見別名
import numpy as np  # numpy → np
import pandas as pd  # pandas → pd
import matplotlib.pyplot as plt  # matplotlib.pyplot → plt
# 爬蟲領(lǐng)域的常見別名
import requests as req  # requests → req
from bs4 import BeautifulSoup as bs  # BeautifulSoup → bs

from module1 import func as func1
from module2 import func as func2
# 調(diào)用時不會沖突
func1()
func2()

from datetime import datetime as dt  # datetime 類 → dt
from os import path as osp  # os.path → osp
print(dt.now())  # 等價于 datetime.now()
print(osp.exists("test.txt"))  # 等價于 os.path.exists()

# 將文件對象綁定到變量 f，通過 f 操作文件
with open("data.csv", "r", encoding="utf-8") as f:
    content = f.read()  # 讀取文件內(nèi)容
    lines = f.readlines()  # 按行讀取

# with 塊結(jié)束后，文件會自動關(guān)閉，無需手動 f.close()

import sqlite3
# 將數(shù)據(jù)庫連接對象綁定到變量 conn
with sqlite3.connect("test.db") as conn:
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM users")  # 執(zhí)行SQL
    result = cursor.fetchall()

import requests
# 將響應(yīng)對象綁定到變量 res
with requests.get("https://www.baidu.com") as res:
    print(res.status_code)  # 獲取響應(yīng)狀態(tài)碼
    print(res.text)  # 獲取響應(yīng)內(nèi)容

import re
pattern = r"(?P<year>\d{4})-(?P<month>\d{2})-(?P<day>\d{2})"
match = re.match(pattern, "2025-12-22")
# 訪問命名分組，等價于 match.group(1)、match.group(2)
print(match.group("year"))  # 輸出：2025
print(match.group("month"))  # 輸出：12

from typing import TypeAlias
# 定義別名：MovieData 是字典類型的別名
MovieData: TypeAlias = dict[str, str | int]
# 使用別名
def process_movie(data: MovieData) -> None:
    print(data["name"])
process_movie({"name": "肖申克的救贖", "score": 9.7})

import aiohttp
import asyncio
async def fetch_url(url: str):
    # 異步上下文管理器，綁定響應(yīng)對象到 res
    async with aiohttp.ClientSession() as session:
        async with session.get(url) as res:
            return await res.text()
# 執(zhí)行異步函數(shù)
asyncio.run(fetch_url("https://www.baidu.com"))

try:
    10 / 0
except ZeroDivisionError as e:
    print(e)  # 有效
print(e)  # 報錯：NameError: name 'e' is not defined