Python 开发配置速查表

虚拟环境管理 (py-env)

``bash # 创建虚拟环境 python -m venv venv

# 激活虚拟环境 (Linux/macOS) source venv/bin/activate

# 激活虚拟环境 (Windows PowerShell) venv\Scripts\Activate.ps1

# 退出虚拟环境 deactivate

# 导出已安装包列表 pip freeze > requirements.txt

# 从 requirements 文件安装 pip install -r requirements.txt `

包管理 (py-env)

`bash # 安装包 pip install requests

# 安装指定版本 pip install requests==2.31.0

# 升级包 pip install --upgrade requests

# 卸载包 pip uninstall requests -y

# 列出已安装包 pip list

# 查看包详细信息 pip show requests

# 安装到用户目录（无 sudo） pip install --user package

# 检查可升级的包 pip list --outdated `

核心数据类型 (py-data)

`python # 列表操作 lst = [1, 2, 3] lst.append(4) # [1, 2, 3, 4] lst.extend([5, 6]) # [1, 2, 3, 4, 5, 6] lst.insert(0, 0) # [0, 1, 2, 3, 4, 5, 6] lst.remove(3) # [0, 1, 2, 4, 5, 6] popped = lst.pop() # popped=6, lst=[0, 1, 2, 4, 5]

# 字典操作 d = {'a': 1, 'b': 2} d['c'] = 3 # {'a': 1, 'b': 2, 'c': 3} d.get('x', 0) # 0 (带默认值) d.setdefault('y', 4) # 键不存在时设置默认值 d.keys() # dict_keys(['a', 'b', 'c']) d.values() # dict_values([1, 2, 3]) d.items() # dict_items([('a',1), ('b',2), ('c',3)])

# 集合操作 s = {1, 2, 3} s.add(4) # {1, 2, 3, 4} s.discard(2) # {1, 3, 4} s1 = {1, 2, 3} s2 = {3, 4, 5} s1 & s2 # {3} 交集 s1 | s2 # {1,2,3,4,5} 并集 s1 - s2 # {1, 2} 差集 `

字符串处理 (py-string)

`python s = " hello world " s.strip() # "hello world" s.upper() # " HELLO WORLD " s.lower() # " hello world " s.split() # ['hello', 'world'] '-'.join(['a','b']) # "a-b" s.replace("world", "python") # " hello python " s.startswith("hel") # True s.find("world") # 8 s.count("l") # 3

# f-string 格式化 name = "Alice" age = 30 f"Name: {name}, Age: {age}" # "Name: Alice, Age: 30" f"{3.14159:.2f}" # "3.14" f"{1000:>10}" # " 1000" (右对齐)

# 字符串切片 text = "python" text[0:3] # "pyt" text[::-1] # "nohtyp" text[::2] # "pto" `

文件 IO (py-file)

`python # 读取文件 with open('file.txt', 'r', encoding='utf-8') as f: content = f.read() # 全部读取 lines = f.readlines() # 逐行读取到列表 for line in f: # 逐行迭代（内存友好） print(line.strip())

# 写入文件 with open('file.txt', 'w', encoding='utf-8') as f: f.write('hello\n') f.writelines(['line1\n', 'line2\n'])

# 追加写入 with open('file.txt', 'a', encoding='utf-8') as f: f.write('append this\n')

# JSON 文件操作 import json data = {'name': 'Alice', 'scores': [90, 85]} with open('data.json', 'w') as f: json.dump(data, f, indent=2) with open('data.json') as f: loaded = json.load(f)

# 路径操作 from pathlib import Path p = Path('/home/user/file.txt') p.name # "file.txt" p.stem # "file" p.suffix # ".txt" p.parent # "/home/user" p.exists() # True/False p.mkdir(parents=True, exist_ok=True) `

模块与参数解析 (py-module)

`python # argparse 命令行参数 import argparse parser = argparse.ArgumentParser(description='My script') parser.add_argument('input', help='输入文件路径') parser.add_argument('-o', '--output', default='out.txt', help='输出文件') parser.add_argument('-v', '--verbose', action='store_true', help='详细输出') parser.add_argument('--count', type=int, default=1, help='次数') args = parser.parse_args()

# sys 模块 import sys sys.argv # 命令行参数列表 sys.exit(0) # 正常退出 sys.exit(1) # 错误退出 sys.path # Python 模块搜索路径

# os 模块 import os os.getcwd() # 当前工作目录 os.listdir('.') # 列出目录内容 os.environ.get('HOME') # 环境变量 os.path.join('dir', 'file.txt') # 路径拼接 `

日期与随机 (py-module)

`python # datetime from datetime import datetime, timedelta now = datetime.now() now.strftime('%Y-%m-%d %H:%M:%S') # "2026-07-16 15:30:00" datetime.strptime('2026-07-16', '%Y-%m-%d') now + timedelta(days=7) # 一周后 now - timedelta(hours=3) # 三小时前

# random import random random.random() # [0.0, 1.0) 随机浮点数 random.randint(1, 10) # [1, 10] 随机整数 random.choice(['a','b','c']) # 随机选择一个 random.sample(range(100), 5) # 不重复随机抽样 random.shuffle(list) # 原地打乱列表 `

输入输出与格式化 (py-io)

`python # 输入 user_input = input("Enter name: ")

# print 高级用法 print("hello", "world", sep=", ") # hello, world print("loading", end="...\n") # 自定义结尾 print(f"值: {value:>10.2f}") # 右对齐保留两位小数

# 异常处理 try: result = 10 / 0 except ZeroDivisionError as e: print(f"错误: {e}") except (ValueError, TypeError): print("类型或值错误") else: print("无异常") finally: print("始终执行")

# 主动抛出异常 raise ValueError("invalid value") `

列表推导与调试 (py-debug)

``python # 列表推导式 squares = [x2 for x in range(10)] # [0, 1, 4, ..., 81] evens = [x for x in range(20) if x % 2 == 0] pairs = [(x, y) for x in [1,2] for y in [3,4]] # [(1,3),(1,4),(2,3),(2,4)]

# 字典推导式 square_dict = {x: x2 for x in range(5)} # {0:0, 1:1, 2:4, 3:9, 4:16}

# 集合推导式 unique_lens = {len(w) for w in ["hi", "hello", "hey"]} # {2, 3, 5}

# 生成器表达式 gen = (x2 for x in range(1000000)) # 惰性求值，内存友好 sum(x2 for x in range(10)) # 285

# 调试打印 from pprint import pprint data = {'users': [{'name': 'Alice', 'age': 30}, {'name': 'Bob', 'age': 25}]} pprint(data, indent=2, depth=2)

# 断点调试 (Python 3.7+) # breakpoint() # 启动 pdb 调试器

# 计时装饰器 import time def timer(func): def wrapper(*args, **kwargs): start = time.perf_counter() result = func(*args, **kwargs) elapsed = time.perf_counter() - start print(f"{func.__name__} 耗时: {elapsed:.4f}s") return result return wrapper

@timer def slow_function(): time.sleep(0.1) return "done"