Python \u7684\u8bbe\u8ba1\u54f2\u5b66\u6df1\u6df1\u690d\u6839\u4e8e\u5176\u8bed\u6cd5\u548c\u6807\u51c6\u5e93\u4e2d\u3002\u901a\u8fc7\u5728\u89e3\u91ca\u5668\u4e2d\u8fd0\u884c Python 3 \u4e8e 2008 \u5e74\u53d1\u5e03\uff0c\u65e8\u5728\u4fee\u590d Python 2 \u4e2d\u7684\u6839\u672c\u6027\u8bbe\u8ba1\u7f3a\u9677\u3002<\/p>\n\n\n\n GIL (Global Interpreter Lock) \u662f CPython \u89e3\u91ca\u5668\u4e2d\u7684\u4e00\u4e2a\u4e92\u65a5\u9501\uff0c\u5b83\u786e\u4fdd\u540c\u4e00\u65f6\u523b\u53ea\u6709\u4e00\u4e2a\u7ebf\u7a0b\u6267\u884c Python \u5b57\u8282\u7801\u3002<\/p>\n\n\n\n \u5728\u73b0\u4ee3\u8f6f\u4ef6\u5f00\u53d1\u4e2d\uff0c\u4f9d\u8d56\u9694\u79bb\u548c\u53ef\u91cd\u590d\u6784\u5efa\u662f\u81f3\u5173\u91cd\u8981\u7684\u3002<\/p>\n\n\n\n \u865a\u62df\u73af\u5883\u4e3a\u6bcf\u4e2a\u9879\u76ee\u521b\u5efa\u4e86\u72ec\u7acb\u7684 Python \u8fd0\u884c\u65f6\u548c\u5305\u5b89\u88c5\u76ee\u5f55\uff0c\u907f\u514d\u5168\u5c40\u6c61\u67d3\u3002<\/p>\n\n\n\n PEP 518 \u548c PEP 621 \u786e\u7acb\u4e86 [project]<\/p>\n\n\n\n name = “my_awesome_project” version = “0.1.0” description = “A demonstration of modern Python packaging” requires-python = “>=3.10” dependencies = [ “requests>=2.28.0”, “pydantic>=2.0.0”, ]<\/p>\n\n\n [project.optional-dependencies]<\/p>\n\n\n\n dev = [ “pytest>=7.0.0”, “black>=23.0.0”, ]<\/p>\n\n\n\n \u5728 Python \u4e2d\uff0c\u53d8\u91cf\u53ea\u662f\u5bf9\u8c61\u7684\u5f15\u7528\uff08\u6807\u7b7e\uff09<\/strong>\uff0c\u5bf9\u8c61\u672c\u8eab\u5b58\u50a8\u5728\u5806\u5185\u5b58\u4e2d\u3002<\/p>\n\n\n\n \u6700\u4f73\u5b9e\u8df5<\/strong>\uff1a\u5904\u7406\u5927\u89c4\u6a21\u6570\u636e\u6d41\u6216\u53ea\u9700\u904d\u5386\u4e00\u6b21\u7684\u6570\u636e\u65f6\uff0c\u6c38\u8fdc\u4f18\u5148\u4f7f\u7528\u751f\u6210\u5668<\/strong>\u3002<\/p>\n\n\n\n \u5728 Python \u4e2d\uff0c\u51fd\u6570\u662f\u5bf9\u8c61\uff0c\u53ef\u4ee5\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u3001\u4f5c\u4e3a\u8fd4\u56de\u503c\uff0c\u6216\u8d4b\u503c\u7ed9\u53d8\u91cf\u3002 \u88c5\u9970\u5668\u672c\u8d28\u4e0a\u662f\u4e00\u4e2a\u63a5\u53d7\u51fd\u6570\u4f5c\u4e3a\u53c2\u6570\u5e76\u8fd4\u56de\u65b0\u51fd\u6570\u7684\u9ad8\u9636\u51fd\u6570\u3002\u5e38\u7528\u4e8e\u65e5\u5fd7\u3001\u9274\u6743\u3001\u7f13\u5b58\u3002<\/p>\n\n\n\n \u57fa\u7840\u88c5\u9970\u5668<\/strong>\uff1a<\/p>\n\n\n\n \u5e26\u53c2\u6570\u7684\u88c5\u9970\u5668<\/strong>\uff08\u9700\u8981\u4e09\u5c42\u5d4c\u5957\uff09\uff1a<\/p>\n\n\n\n \u4efb\u4f55\u5b9e\u73b0\u4e86 \u9b54\u672f\u65b9\u6cd5\uff08\u53cc\u4e0b\u5212\u7ebf\u65b9\u6cd5\uff09\u5141\u8bb8\u81ea\u5b9a\u4e49\u7c7b\u53c2\u4e0e Python \u7684\u6838\u5fc3\u8bed\u6cd5\u64cd\u4f5c\u3002<\/p>\n\n\n\n Python \u652f\u6301\u591a\u91cd\u7ee7\u627f\uff0c\u4f7f\u7528 C3 \u7ebf\u6027\u5316\u7b97\u6cd5 (C3 Linearization)<\/strong> \u6765\u51b3\u5b9a\u65b9\u6cd5\u8c03\u7528\u7684\u987a\u5e8f\uff0c\u907f\u514d\u83f1\u5f62\u7ee7\u627f\u95ee\u9898\u3002<\/p>\n\n\n\n \u201c\u7c7b\u662f\u521b\u5efa\u5b9e\u4f8b\u7684\u6a21\u677f\uff0c\u800c\u5143\u7c7b\u662f\u521b\u5efa\u7c7b\u7684\u6a21\u677f\u201d\u3002\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cPython \u4e2d\u6240\u6709\u7c7b\u7684\u5143\u7c7b\u90fd\u662f import this<\/code>\uff0c\u6211\u4eec\u53ef\u4ee5\u7aa5\u89c1\u5176\u6838\u5fc3\u601d\u60f3\uff1a<\/p>\n\n\n\n\n
\n
1.2 Python 2 \u5230 Python 3 \u7684\u6f14\u8fdb\u4e0e\u73b0\u72b6<\/h3>\n\n\n\n
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str<\/code> \u9ed8\u8ba4\u4e3a Unicode\uff0cbytes<\/code> \u7528\u4e8e\u8868\u793a\u5b57\u8282\u5e8f\u5217\uff0c\u5f7b\u5e95\u89e3\u51b3\u4e86\u591a\u8bed\u8a00\u7f16\u7801\u75db\u70b9\u3002<\/li>\n\n\n\nprint<\/code> \u4ece\u8bed\u53e5\u53d8\u4e3a\u51fd\u6570 print()<\/code>\uff0c\u63d0\u9ad8\u4e86\u8bed\u6cd5\u7684\u4e00\u81f4\u6027\u3002<\/li>\n\n\n\nint<\/code> \u548c long<\/code> \u7684\u533a\u522b\uff0c\u6240\u6709\u6574\u6570\u5747\u4e3a\u4efb\u610f\u7cbe\u5ea6\u3002<\/li>\n\n\n\n1.3 \u5168\u5c40\u89e3\u91ca\u5668\u9501 (GIL) \u7684\u6df1\u5ea6\u89e3\u6790<\/h3>\n\n\n\n
\n
\n
multiprocessing<\/code> \u6a21\u5757\u7ed5\u8fc7 GIL\uff0c\u5229\u7528\u591a\u6838\u3002<\/li>\n\n\n\nasyncio<\/code>) \u5904\u7406\u9ad8\u5e76\u53d1\u7f51\u7edc\u8bf7\u6c42\u3002<\/li>\n\n\n\n
\n\n\n\n\u7b2c\u4e8c\u90e8\u5206\uff1a\u73b0\u4ee3 Python \u5de5\u7a0b\u5316\u4e0e\u73af\u5883\u7ba1\u7406<\/h2>\n\n\n\n
2.1 \u865a\u62df\u73af\u5883 (Virtual Environments)<\/h3>\n\n\n\n
# 1. \u4f7f\u7528\u5185\u7f6e venv \u521b\u5efa\u865a\u62df\u73af\u5883 (\u63a8\u8350)\npython3 -m venv myenv\n\n# 2. \u6fc0\u6d3b\u865a\u62df\u73af\u5883\n# macOS \/ Linux:\nsource myenv\/bin\/activate\n# Windows:\nmyenv\\Scripts\\activate\n\n# 3. \u9a8c\u8bc1\u73af\u5883\u9694\u79bb\nwhich python # \u5e94\u6307\u5411 myenv \u76ee\u5f55\u4e0b\u7684 python<\/code><\/pre>\n\n\n\n2.2 \u73b0\u4ee3\u4f9d\u8d56\u7ba1\u7406\u5de5\u5177\u5bf9\u6bd4<\/h3>\n\n\n\n
\u5de5\u5177<\/th> \u7279\u70b9<\/th> \u9002\u7528\u573a\u666f<\/th><\/tr><\/thead> pip<\/code> + requirements.txt<\/code><\/td>\u5b98\u65b9\u57fa\u7840\u5de5\u5177\uff0c\u7b80\u5355\u76f4\u63a5\u3002<\/td> \u5c0f\u578b\u811a\u672c\u3001Docker \u955c\u50cf\u6784\u5efa\u3002<\/td><\/tr> Poetry<\/code><\/td>\u73b0\u4ee3\u4f9d\u8d56\u7ba1\u7406\uff0c\u652f\u6301 pyproject.toml<\/code>\uff0c\u81ea\u52a8\u89e3\u51b3\u4f9d\u8d56\u51b2\u7a81\uff0c\u5185\u7f6e\u53d1\u5e03\u529f\u80fd\u3002<\/td>\u4e2d\u5927\u578b\u9879\u76ee\u3001\u5f00\u6e90\u5e93\u5f00\u53d1\u3002<\/td><\/tr> Pipenv<\/code><\/td>\u7ed3\u5408\u4e86 pip<\/code> \u548c virtualenv<\/code>\uff0c\u4f7f\u7528 Pipfile<\/code> \u548c Pipfile.lock<\/code>\u3002<\/td>\u9700\u8981\u7b80\u5355\u4f9d\u8d56\u9501\u5b9a\u7684 Web \u5e94\u7528\u3002<\/td><\/tr> uv<\/code> (\u65b0\u5174)<\/td>\u7531 Rust \u7f16\u5199\u7684\u8d85\u9ad8\u901f Python \u5305\u5b89\u88c5\u5668\u548c\u89e3\u6790\u5668\uff0c\u517c\u5bb9 pip \u63a5\u53e3\u3002<\/td> \u8ffd\u6c42\u6781\u81f4\u5b89\u88c5\u901f\u5ea6\u7684\u73b0\u4ee3\u9879\u76ee (2024+ \u8d8b\u52bf)\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n 2.3
pyproject.toml<\/code> \u6807\u51c6<\/h3>\n\n\n\npyproject.toml<\/code> \u4f5c\u4e3a Python \u9879\u76ee\u914d\u7f6e\u7684\u5355\u4e00\u4e8b\u5b9e\u6765\u6e90\u3002<\/p>\n\n\n\n# pyproject.toml \u793a\u4f8b<\/code><\/pre>\n\n\n
\n\n\n\n\u7b2c\u4e09\u90e8\u5206\uff1a\u6838\u5fc3\u8bed\u6cd5\u4e0e\u6570\u636e\u6a21\u578b\u5e95\u5c42\u5256\u6790<\/h2>\n\n\n\n
3.1 \u53d8\u91cf\u4e0e\u5185\u5b58\u7ba1\u7406\uff1a\u5f15\u7528\u8ba1\u6570\u4e0e\u5783\u573e\u56de\u6536<\/h3>\n\n\n\n
\n
ob_refcnt<\/code>\u3002\u5f53\u5f15\u7528\u8ba1\u6570\u5f52\u96f6\u65f6\uff0c\u5185\u5b58\u7acb\u5373\u88ab\u91ca\u653e\u3002<\/li>\n<\/ul>\n\n\n\n import sys\n a = [1, 2, 3]\n print(sys.getrefcount(a)) # \u8f93\u51fa\u901a\u5e38\u4e3a 2 (a \u7684\u5f15\u7528 + getrefcount \u53c2\u6570\u5f15\u7528)\n b = a\n print(sys.getrefcount(a)) # \u8f93\u51fa 3\n del b\n print(sys.getrefcount(a)) # \u8f93\u51fa 2<\/code><\/pre>\n\n\n\n\n
3.2 \u5b57\u7b26\u4e32 (str) \u7684\u5e95\u5c42\u673a\u5236<\/h3>\n\n\n\n
\n
a = \"hello_world\"\n b = \"hello_world\"\n print(a is b) # True\uff0c\u6307\u5411\u540c\u4e00\u4e2a\u5185\u5b58\u5730\u5740\n\n c = \"hello-world!\"\n d = \"hello-world!\"\n print(c is d) # False (\u53d6\u51b3\u4e8e\u5177\u4f53 Python \u7248\u672c\u548c\u7f16\u8bd1\u5668\u4f18\u5316\uff0c\u901a\u5e38\u5305\u542b\u7279\u6b8a\u5b57\u7b26\u4e0d\u9a7b\u7559)<\/code><\/pre>\n\n\n\n\n
%<\/code> \u683c\u5f0f\u5316\u548c .format()<\/code>\u3002<\/li>\n<\/ul>\n\n\n\n3.3 \u6838\u5fc3\u6570\u636e\u7ed3\u6784\u5e95\u5c42\u5b9e\u73b0\u4e0e\u65f6\u95f4\u590d\u6742\u5ea6<\/h3>\n\n\n\n
\u5217\u8868 (List)<\/h4>\n\n\n\n
\n
lst[i]<\/code>\uff1a$O(1)$<\/li>\n\n\n\nlst.append()<\/code>\uff1a\u5747\u644a $O(1)$<\/li>\n\n\n\nlst.insert(0, x)<\/code>\uff1a$O(n)$ (\u9700\u8981\u79fb\u52a8\u6240\u6709\u540e\u7eed\u5143\u7d20)<\/li>\n<\/ul>\n\n\n\n\u5b57\u5178 (Dict) \u4e0e \u96c6\u5408 (Set)<\/h4>\n\n\n\n
\n
str<\/code>, int<\/code>, tuple<\/code>\uff09\uff0c\u53ef\u53d8\u5bf9\u8c61\uff08\u5982 list<\/code>, dict<\/code>\uff09\u4e0d\u80fd\u4f5c\u4e3a\u952e\u3002<\/li>\n<\/ul>\n\n\n\n3.4 \u63a8\u5bfc\u5f0f (Comprehensions) vs \u751f\u6210\u5668 (Generators)<\/h3>\n\n\n\n
# \u5217\u8868\u63a8\u5bfc\u5f0f\uff1a\u7acb\u5373\u8ba1\u7b97\u6240\u6709\u5143\u7d20\uff0c\u5360\u7528 O(n) \u5185\u5b58\nsquares_list = [x**2 for x in range(1000000)] \n\n# \u751f\u6210\u5668\u8868\u8fbe\u5f0f\uff1a\u60f0\u6027\u6c42\u503c (Lazy Evaluation)\uff0c\u6bcf\u6b21 yield \u4e00\u4e2a\u503c\uff0c\u5360\u7528 O(1) \u5185\u5b58\nsquares_gen = (x**2 for x in range(1000000))\n\nprint(next(squares_gen)) # 0\nprint(next(squares_gen)) # 1<\/code><\/pre>\n\n\n\n
\n\n\n\n\u7b2c\u56db\u90e8\u5206\uff1a\u51fd\u6570\u5f0f\u7f16\u7a0b\u4e0e\u9ad8\u7ea7\u7279\u6027<\/h2>\n\n\n\n
4.1 \u4e00\u7b49\u516c\u6c11\u51fd\u6570\u4e0e\u95ed\u5305 (Closures)<\/h3>\n\n\n\n
\u95ed\u5305<\/strong>\u662f\u6307\u4e00\u4e2a\u51fd\u6570\u8bb0\u4f4f\u4e86\u5176\u5b9a\u4e49\u65f6\u7684\u8bcd\u6cd5\u73af\u5883\uff0c\u5373\u4f7f\u8be5\u73af\u5883\u5df2\u7ecf\u4e0d\u5728\u5185\u5b58\u4e2d\u3002<\/p>\n\n\n\ndef make_multiplier(factor):\n # factor \u662f\u81ea\u7531\u53d8\u91cf\uff0c\u88ab\u5185\u90e8\u51fd\u6570\u6355\u83b7\n def multiplier(x):\n return x * factor\n return multiplier\n\ndouble = make_multiplier(2)\nprint(double(5)) # \u8f93\u51fa: 10\nprint(double.__closure__[0].cell_contents) # \u67e5\u770b\u6355\u83b7\u7684\u53d8\u91cf: 2<\/code><\/pre>\n\n\n\n4.2 \u88c5\u9970\u5668 (Decorators) \u6df1\u5ea6\u89e3\u6790<\/h3>\n\n\n\n
import functools\nimport time\n\ndef timer(func):\n @functools.wraps(func) # \u5173\u952e\uff1a\u4fdd\u7559\u539f\u51fd\u6570\u7684\u5143\u6570\u636e (__name__, __doc__)\n def wrapper(*args, **kwargs):\n start_time = time.perf_counter()\n result = func(*args, **kwargs)\n end_time = time.perf_counter()\n print(f\"\u51fd\u6570 {func.__name__} \u6267\u884c\u8017\u65f6: {end_time - start_time:.4f} \u79d2\")\n return result\n return wrapper\n\n@timer\ndef heavy_computation(n):\n return sum(i * i for i in range(n))\n\nheavy_computation(10_000_000)<\/code><\/pre>\n\n\n\ndef retry(max_attempts):\n def decorator(func):\n @functools.wraps(func)\n def wrapper(*args, **kwargs):\n for attempt in range(max_attempts):\n try:\n return func(*args, **kwargs)\n except Exception as e:\n print(f\"Attempt {attempt + 1} failed: {e}\")\n raise RuntimeError(\"Max retries exceeded\")\n return wrapper\n return decorator\n\n@retry(max_attempts=3)\ndef unstable_api_call():\n # \u6a21\u62df\u4e0d\u7a33\u5b9a\u64cd\u4f5c\n pass<\/code><\/pre>\n\n\n\n4.3 \u8fed\u4ee3\u5668\u534f\u8bae\u4e0e
yield<\/code><\/h3>\n\n\n\n__iter__()<\/code> \u548c __next__()<\/code> \u65b9\u6cd5\u7684\u5bf9\u8c61\u90fd\u662f\u8fed\u4ee3\u5668\u3002yield<\/code> \u5173\u952e\u5b57\u5c06\u666e\u901a\u51fd\u6570\u8f6c\u53d8\u4e3a\u751f\u6210\u5668\u51fd\u6570\u3002<\/p>\n\n\n\ndef fibonacci(limit):\n a, b = 0, 1\n while a < limit:\n yield a\n a, b = b, a + b\n\n# yield from (Python 3.3+) \u7528\u4e8e\u59d4\u6258\u751f\u6210\u5668\uff0c\u7b80\u5316\u5d4c\u5957\u751f\u6210\u5668\u7684\u7f16\u5199\ndef read_file_lines(file_path):\n with open(file_path, 'r') as f:\n yield from f # \u7b49\u540c\u4e8e for line in f: yield line<\/code><\/pre>\n\n\n\n
\n\n\n\n\u7b2c\u4e94\u90e8\u5206\uff1a\u9762\u5411\u5bf9\u8c61\u7f16\u7a0b (OOP) \u4e0e\u5143\u7f16\u7a0b<\/h2>\n\n\n\n
5.1 \u7c7b\u4e0e\u5b9e\u4f8b\u7684\u5185\u5b58\u5e03\u5c40<\/h3>\n\n\n\n
\n
__dict__<\/code><\/strong>\uff1a\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cPython \u5bf9\u8c61\u7684\u5c5e\u6027\u5b58\u50a8\u5728\u4e00\u4e2a\u5b57\u5178\u4e2d\uff0c\u8fd9\u63d0\u4f9b\u4e86\u6781\u5927\u7684\u52a8\u6001\u6027\uff0c\u4f46\u6d88\u8017\u8f83\u591a\u5185\u5b58\u3002<\/li>\n\n\n\n__slots__<\/code><\/strong>\uff1a\u901a\u8fc7\u663e\u5f0f\u58f0\u660e\u5141\u8bb8\u7684\u5c5e\u6027\u540d\u79f0\uff0cPython \u4f1a\u963b\u6b62\u521b\u5efa __dict__<\/code>\uff0c\u4ece\u800c\u5927\u5e45\u8282\u7701\u5185\u5b58\u5e76\u63d0\u9ad8\u5c5e\u6027\u8bbf\u95ee\u901f\u5ea6\uff08\u9002\u7528\u4e8e\u9700\u8981\u521b\u5efa\u6570\u767e\u4e07\u4e2a\u5b9e\u4f8b\u7684\u573a\u666f\uff09\u3002<\/li>\n<\/ul>\n\n\n\n class Point:\n __slots__ = ['x', 'y'] # \u7981\u6b62\u52a8\u6001\u6dfb\u52a0\u5176\u4ed6\u5c5e\u6027\n def __init__(self, x, y):\n self.x = x\n self.y = y<\/code><\/pre>\n\n\n\n5.2 \u9b54\u672f\u65b9\u6cd5 (Dunder Methods) \u5b8c\u6574\u6307\u5357<\/h3>\n\n\n\n
\n
__new__<\/code> (\u63a7\u5236\u5bf9\u8c61\u521b\u5efa\uff0c\u5e38\u7528\u4e8e\u5355\u4f8b\u6a21\u5f0f), __init__<\/code> (\u521d\u59cb\u5316), __del__<\/code> (\u6790\u6784\uff0c\u4f46\u4e0d\u4fdd\u8bc1\u7acb\u5373\u6267\u884c)\u3002<\/li>\n\n\n\n__str__<\/code> (\u9762\u5411\u7528\u6237\uff0cprint()<\/code> \u8c03\u7528), __repr__<\/code> (\u9762\u5411\u5f00\u53d1\u8005\uff0c\u8c03\u8bd5\u65f6\u4f7f\u7528\uff0c\u5e94\u5c3d\u53ef\u80fd\u8fd4\u56de\u53ef\u91cd\u5efa\u5bf9\u8c61\u7684\u4ee3\u7801)\u3002<\/li>\n\n\n\n__len__<\/code>, __getitem__<\/code>, __setitem__<\/code>, __contains__<\/code> (\u652f\u6301 in<\/code> \u64cd\u4f5c\u7b26)\u3002<\/li>\n\n\n\n__enter__<\/code>, __exit__<\/code> (\u652f\u6301 with<\/code> \u8bed\u53e5)\u3002<\/li>\n<\/ul>\n\n\n\n class DatabaseConnection:\n def __enter__(self):\n self.conn = connect_to_db()\n return self.conn\n\n def __exit__(self, exc_type, exc_val, exc_tb):\n self.conn.close()\n if exc_type is not None:\n print(f\"\u53d1\u751f\u5f02\u5e38: {exc_val}\")\n return False # \u4e0d\u6291\u5236\u5f02\u5e38<\/code><\/pre>\n\n\n\n5.3 \u591a\u91cd\u7ee7\u627f\u4e0e MRO (\u65b9\u6cd5\u89e3\u6790\u987a\u5e8f)<\/h3>\n\n\n\n
class A:\n def process(self): print(\"A\")\n\nclass B(A):\n def process(self): \n super().process()\n print(\"B\")\n\nclass C(A):\n def process(self): \n super().process()\n print(\"C\")\n\nclass D(B, C):\n def process(self): \n super().process()\n print(\"D\")\n\nd = D()\nd.process()\n# \u8f93\u51fa\u987a\u5e8f: A -> C -> B -> D\n# \u53ef\u901a\u8fc7 D.mro() \u67e5\u770b\u89e3\u6790\u987a\u5e8f: [<class 'D'>, <class 'B'>, <class 'C'>, <class 'A'>, <class 'object'>]<\/code><\/pre>\n\n\n\n5.4 \u5143\u7c7b (Metaclasses) \u7b80\u4ecb<\/h3>\n\n\n\n
type<\/code>\u3002
\u5e94\u7528\u573a\u666f<\/strong>\uff1aORM \u6846\u67b6\uff08\u5982 Django \u7684 Models\uff09\u3001API \u6ce8\u518c\u8868\u3001\u5f3a\u5236\u4ee3\u7801\u89c4\u8303\u3002<\/p>\n\n\n\nclass SingletonMeta(type):\n _instances = {}\n def __call__(cls, *args, **kwargs):\n if cls not in cls._instances:\n cls._instances[cls] = super().__call__(*args, **kwargs)\n return cls._instances[cls]\n\nclass Database(metaclass=SingletonMeta):\n pass\n\ndb1 = Database()\ndb2 = Database()\nprint(db1 is db2) # True<\/code><\/pre>\n\n\n\n
\n\n\n\n\u7b2c\u516d\u90e8\u5206\uff1a\u5e76\u53d1\u7f16\u7a0b\u4e0e\u5f02\u6b65 I\/O (Asyncio)<\/h2>\n\n\n\n
6.1 \u591a\u7ebf\u7a0b (Threading) vs \u591a\u8fdb\u7a0b (Multiprocessing)<\/h3>\n\n\n\n
\u7279\u6027<\/th> threading<\/code> (\u591a\u7ebf\u7a0b)<\/th>multiprocessing<\/code> (\u591a\u8fdb\u7a0b)<\/th><\/tr><\/thead>\u5185\u5b58\u5171\u4eab<\/strong><\/td> \u5171\u4eab\u540c\u4e00\u8fdb\u7a0b\u7684\u5185\u5b58\u7a7a\u95f4<\/td> \u72ec\u7acb\u7684\u5185\u5b58\u7a7a\u95f4 (\u9700\u901a\u8fc7 Queue\/Pipe \u901a\u4fe1)<\/td><\/tr> GIL \u9650\u5236<\/strong><\/td> \u53d7 GIL \u9650\u5236\uff0c\u65e0\u6cd5\u5e76\u884c\u6267\u884c CPU \u5bc6\u96c6\u578b Python \u4ee3\u7801<\/td> \u6bcf\u4e2a\u8fdb\u7a0b\u6709\u72ec\u7acb\u7684 Python \u89e3\u91ca\u5668\u548c GIL\uff0c\u53ef\u771f\u6b63\u5229\u7528\u591a\u6838<\/td><\/tr> \u5f00\u9500<\/strong><\/td> \u521b\u5efa\u548c\u5207\u6362\u5f00\u9500\u5c0f<\/td> \u521b\u5efa\u548c\u5207\u6362\u5f00\u9500\u5927 (\u6d89\u53ca OS \u8fdb\u7a0b\u8c03\u5ea6)<\/td><\/tr> \u9002\u7528\u573a\u666f<\/strong><\/td> I\/O \u5bc6\u96c6\u578b (\u7f51\u7edc\u722c\u866b\u3001\u6587\u4ef6\u8bfb\u5199)<\/td> CPU \u5bc6\u96c6\u578b (\u56fe\u50cf\u5904\u7406\u3001\u5927\u89c4\u6a21\u6570\u503c\u8ba1\u7b97)<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n 6.2 \u5f02\u6b65\u7f16\u7a0b (Asyncio) \u6838\u5fc3\u6982\u5ff5<\/h3>\n\n\n\n
asyncio<\/code> \u662f Python 3.4+ \u5f15\u5165\u7684\u6807\u51c6\u5e93\uff0c\u7528\u4e8e\u7f16\u5199\u5355\u7ebf\u7a0b\u5e76\u53d1\u4ee3\u7801\u3002\u5b83\u57fa\u4e8e\u4e8b\u4ef6\u5faa\u73af (Event Loop)<\/strong>\u3001\u534f\u7a0b (Coroutines)<\/strong>\u3001\u4efb\u52a1 (Tasks)<\/strong> \u548c Future<\/strong> \u6784\u5efa\u3002<\/p>\n\n\n\nimport asyncio\nimport aiohttp\nimport time\n\nasync def fetch_data(session, url):\n print(f\"\u5f00\u59cb\u8bf7\u6c42: {url}\")\n async with session.get(url) as response:\n # await \u6302\u8d77\u5f53\u524d\u534f\u7a0b\uff0c\u8ba9\u51fa\u63a7\u5236\u6743\u7ed9\u4e8b\u4ef6\u5faa\u73af\uff0c\u76f4\u5230 I\/O \u5b8c\u6210\n data = await response.text()\n print(f\"\u5b8c\u6210\u8bf7\u6c42: {url}, \u957f\u5ea6: {len(data)}\")\n return len(data)\n\nasync def main():\n urls = [\n \"https:\/\/httpbin.org\/delay\/1\",\n \"https:\/\/httpbin.org\/delay\/2\",\n \"https:\/\/httpbin.org\/delay\/1\"\n ]\n\n start_time = time.perf_counter()\n\n # \u521b\u5efa\u5355\u4e00\u7684 aiohttp \u4f1a\u8bdd\uff0c\u590d\u7528 TCP \u8fde\u63a5\n async with aiohttp.ClientSession() as session:\n # \u521b\u5efa\u4efb\u52a1\u5217\u8868\n tasks = [fetch_data(session, url) for url in urls]\n # asyncio.gather \u5e76\u53d1\u6267\u884c\u6240\u6709\u4efb\u52a1\uff0c\u5e76\u7b49\u5f85\u5b83\u4eec\u5168\u90e8\u5b8c\u6210\n results = await asyncio.gather(*tasks)\n\n end_time = time.perf_counter()\n print(f\"\u603b\u8017\u65f6: {end_time - start_time:.2f} \u79d2\")\n print(f\"\u7ed3\u679c: {results}\")\n\n# Python 3.7+ \u63a8\u8350\u8fd0\u884c\u65b9\u5f0f\nif __name__ == \"__main__\":\n asyncio.run(main())<\/code><\/pre>\n\n\n\n