{"id":70,"date":"2026-06-13T16:59:17","date_gmt":"2026-06-13T08:59:17","guid":{"rendered":"https:\/\/www.52runoob.com\/?p=70"},"modified":"2026-06-13T16:59:17","modified_gmt":"2026-06-13T08:59:17","slug":"python-with-%e5%85%b3%e9%94%ae%e5%ad%97","status":"publish","type":"post","link":"https:\/\/www.52runoob.com\/index.php\/2026\/06\/13\/python-with-%e5%85%b3%e9%94%ae%e5%ad%97\/","title":{"rendered":"Python with \u5173\u952e\u5b57"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\u5728 Python 3 \u4e2d\uff0c<strong><code>with<\/code> \u5173\u952e\u5b57<\/strong>\uff08\u914d\u5408<strong>\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668 Context Manager<\/strong>\uff09\u662f\u8bed\u8a00\u4e2d\u6700\u4f18\u96c5\u3001\u6700\u5f3a\u5927\u7684\u7279\u6027\u4e4b\u4e00\u3002\u5b83\u7684\u6838\u5fc3\u4f7f\u547d\u662f<strong>\u5b89\u5168\u3001\u81ea\u52a8\u5730\u7ba1\u7406\u8d44\u6e90<\/strong>\uff0c\u786e\u4fdd\u65e0\u8bba\u4ee3\u7801\u662f\u6b63\u5e38\u6267\u884c\u5b8c\u6bd5\uff0c\u8fd8\u662f\u4e2d\u9014\u53d1\u751f\u4e86\u5f02\u5e38\uff0c\u8d44\u6e90\uff08\u5982\u6587\u4ef6\u3001\u7f51\u7edc\u8fde\u63a5\u3001\u6570\u636e\u5e93\u8fde\u63a5\u3001\u7ebf\u7a0b\u9501\u7b49\uff09\u90fd\u80fd\u88ab\u6b63\u786e\u91ca\u653e\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u638c\u63e1 <code>with<\/code> \u8bed\u53e5\u53ca\u5176\u80cc\u540e\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u534f\u8bae\uff0c\u4e0d\u4ec5\u80fd\u5e2e\u4f60\u6d88\u9664\u5927\u91cf\u5197\u4f59\u7684 <code>try...finally<\/code> \u4ee3\u7801\uff0c\u8fd8\u80fd\u8ba9\u4f60\u7f16\u5199\u51fa\u66f4\u5065\u58ee\u3001\u66f4\u5177\u201cPythonic\u201d\u98ce\u683c\u7684\u4e13\u4e1a\u7ea7\u4ee3\u7801\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4ee5\u4e0b\u662f\u5bf9 Python 3 <code>with<\/code> \u5173\u952e\u5b57\u7684\u5168\u9762\u3001\u6df1\u5ea6\u89e3\u6790\uff0c\u6db5\u76d6\u5e95\u5c42\u539f\u7406\u3001\u81ea\u5b9a\u4e49\u5b9e\u73b0\u3001\u6807\u51c6\u5e93\u5229\u5668\u53ca\u6700\u4f73\u5b9e\u8df5\u3002\uff08\u672c\u6587\u7bc7\u5e45\u8f83\u957f\uff0c\u65e8\u5728\u63d0\u4f9b\u4e00\u4efd\u53ef\u4f5c\u4e3a\u751f\u4ea7\u73af\u5883\u53c2\u8003\u624b\u518c\u7684\u6df1\u5ea6\u6307\u5357\uff09<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e00\u3001 \u4e3a\u4ec0\u4e48\u9700\u8981 <code>with<\/code>\uff1f\uff08\u75db\u70b9\u4e0e\u89e3\u51b3\u65b9\u6848\uff09<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u6ca1\u6709 <code>with<\/code> \u8bed\u53e5\u7684\u65f6\u4ee3\uff08\u6216\u5728\u4e0d\u652f\u6301\u5b83\u7684\u8bed\u8a00\u4e2d\uff09\uff0c\u7ba1\u7406\u8d44\u6e90\u901a\u5e38\u9700\u8981\u4f7f\u7528 <code>try...finally<\/code> \u5757\u6765\u786e\u4fdd\u6e05\u7406\u4ee3\u7801\u4e00\u5b9a\u4f1a\u88ab\u6267\u884c\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u274c \u4f20\u7edf\u5199\u6cd5\uff1a\u5197\u957f\u4e14\u5bb9\u6613\u51fa\u9519<\/h4>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">file = open(&quot;data.txt&quot;, &quot;w&quot;)\ntry:\n    file.write(&quot;Hello, World!&quot;)\n    # \u5982\u679c\u8fd9\u91cc\u53d1\u751f\u5f02\u5e38\uff0c\u6216\u8005\u5f00\u53d1\u8005\u5fd8\u8bb0\u5199 finally\uff0c\u6587\u4ef6\u5c06\u4e0d\u4f1a\u88ab\u5173\u95ed\n    # \u5bfc\u81f4\u6587\u4ef6\u63cf\u8ff0\u7b26\u6cc4\u6f0f (File Descriptor Leak)\nfinally:\n    file.close()  # \u5fc5\u987b\u624b\u52a8\u786e\u4fdd\u5173\u95ed<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">\u2705 \u73b0\u4ee3 Python \u5199\u6cd5\uff1a\u4f7f\u7528 <code>with<\/code><\/h4>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">with open(&quot;data.txt&quot;, &quot;w&quot;) as file:\n    file.write(&quot;Hello, World!&quot;)\n# \u79bb\u5f00 with \u4ee3\u7801\u5757\u65f6\uff0c\u6587\u4ef6\u4f1a\u81ea\u52a8\u3001\u5b89\u5168\u5730\u5173\u95ed\uff0c\u65e0\u8bba\u662f\u5426\u53d1\u751f\u5f02\u5e38<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u6838\u5fc3\u4f18\u52bf<\/strong>\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u4ee3\u7801\u7b80\u6d01<\/strong>\uff1a\u6d88\u9664\u4e86\u6837\u677f\u4ee3\u7801 (Boilerplate code)\u3002<\/li>\n\n\n\n<li><strong>\u7edd\u5bf9\u5b89\u5168<\/strong>\uff1a\u5373\u4f7f <code>with<\/code> \u5757\u5185\u90e8\u53d1\u751f\u672a\u6355\u83b7\u7684\u5f02\u5e38\uff0c\u6216\u8005\u6267\u884c\u4e86 <code>return<\/code>\u3001<code>break<\/code>\u3001<code>continue<\/code>\uff0c\u6e05\u7406\u903b\u8f91\u4e5f<strong>\u5fc5\u5b9a<\/strong>\u4f1a\u88ab\u6267\u884c\u3002<\/li>\n\n\n\n<li><strong>\u8bed\u4e49\u6e05\u6670<\/strong>\uff1a\u660e\u786e\u8868\u8fbe\u4e86\u201c\u8fd9\u662f\u4e00\u4e2a\u9700\u8981\u7279\u5b9a\u751f\u547d\u5468\u671f\u7ba1\u7406\u7684\u8d44\u6e90\u201d\u3002<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e8c\u3001 <code>with<\/code> \u8bed\u53e5\u7684\u5e95\u5c42\u539f\u7406\uff1a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u534f\u8bae<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><code>with<\/code> \u8bed\u53e5\u672c\u8eab\u5e76\u4e0d\u795e\u5947\uff0c\u5b83\u4f9d\u8d56\u4e8e Python \u7684<strong>\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u534f\u8bae (Context Manager Protocol)<\/strong>\u3002\u4efb\u4f55\u5b9e\u73b0\u4e86\u4ee5\u4e0b\u4e24\u4e2a\u9b54\u672f\u65b9\u6cd5 (Magic Methods) \u7684\u5bf9\u8c61\uff0c\u90fd\u53ef\u4ee5\u7528\u4f5c <code>with<\/code> \u8bed\u53e5\u7684\u76ee\u6807\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong><code>__enter__(self)<\/code><\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u89e6\u53d1\u65f6\u673a<\/strong>\uff1a\u5728\u8fdb\u5165 <code>with<\/code> \u4ee3\u7801\u5757<strong>\u4e4b\u524d<\/strong>\u6267\u884c\u3002<\/li>\n\n\n\n<li><strong>\u4f5c\u7528<\/strong>\uff1a\u521d\u59cb\u5316\u8d44\u6e90\uff08\u5982\u6253\u5f00\u6587\u4ef6\u3001\u83b7\u53d6\u9501\uff09\u3002<\/li>\n\n\n\n<li><strong>\u8fd4\u56de\u503c<\/strong>\uff1a\u8be5\u65b9\u6cd5\u7684\u8fd4\u56de\u503c\u5c06\u88ab\u7ed1\u5b9a\u5230 <code>as<\/code> \u5173\u952e\u5b57\u540e\u9762\u7684\u53d8\u91cf\u4e0a\u3002\u5982\u679c\u6ca1\u6709 <code>as<\/code> \u5b50\u53e5\uff0c\u8fd4\u56de\u503c\u5c06\u88ab\u4e22\u5f03\u3002<\/li>\n<\/ul>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong><code>__exit__(self, exc_type, exc_val, exc_tb)<\/code><\/strong>\uff1a<\/li>\n<\/ol>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u89e6\u53d1\u65f6\u673a<\/strong>\uff1a\u5728\u79bb\u5f00 <code>with<\/code> \u4ee3\u7801\u5757<strong>\u4e4b\u65f6<\/strong>\u6267\u884c\uff08\u65e0\u8bba\u662f\u6b63\u5e38\u79bb\u5f00\u8fd8\u662f\u56e0\u5f02\u5e38\u79bb\u5f00\uff09\u3002<\/li>\n\n\n\n<li><strong>\u4f5c\u7528<\/strong>\uff1a\u6e05\u7406\u8d44\u6e90\uff08\u5982\u5173\u95ed\u6587\u4ef6\u3001\u91ca\u653e\u9501\uff09\u3002<\/li>\n\n\n\n<li><strong>\u53c2\u6570<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li><code>exc_type<\/code>\uff1a\u5f02\u5e38\u7c7b\u578b\uff08\u5982 <code>ValueError<\/code>\uff09\u3002\u5982\u679c\u6ca1\u6709\u5f02\u5e38\uff0c\u5219\u4e3a <code>None<\/code>\u3002<\/li>\n\n\n\n<li><code>exc_val<\/code>\uff1a\u5f02\u5e38\u5b9e\u4f8b\uff08\u5305\u542b\u9519\u8bef\u4fe1\u606f\uff09\u3002\u65e0\u5f02\u5e38\u5219\u4e3a <code>None<\/code>\u3002<\/li>\n\n\n\n<li><code>exc_tb<\/code>\uff1aTraceback \u5bf9\u8c61\uff08\u5f02\u5e38\u5806\u6808\u4fe1\u606f\uff09\u3002\u65e0\u5f02\u5e38\u5219\u4e3a <code>None<\/code>\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>\u8fd4\u56de\u503c (\u6781\u5176\u91cd\u8981)<\/strong>\uff1a\n<ul class=\"wp-block-list\">\n<li>\u5982\u679c\u8fd4\u56de <strong><code>True<\/code><\/strong>\uff1a\u8868\u793a\u8be5\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668<strong>\u5df2\u7ecf\u5904\u7406\u4e86\u5f02\u5e38<\/strong>\uff0c\u5f02\u5e38\u5c06\u88ab<strong>\u541e\u6389 (Suppressed)<\/strong>\uff0c\u4e0d\u4f1a\u5411\u5916\u5c42\u4f20\u64ad\u3002<\/li>\n\n\n\n<li>\u5982\u679c\u8fd4\u56de <strong><code>False<\/code><\/strong> \u6216 <strong><code>None<\/code><\/strong> (\u9ed8\u8ba4\u884c\u4e3a)\uff1a\u5f02\u5e38\u5c06\u88ab<strong>\u91cd\u65b0\u629b\u51fa<\/strong>\uff0c\u4f20\u9012\u7ed9\u5916\u5c42\u4ee3\u7801\u5904\u7406\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">\u5e95\u5c42\u6267\u884c\u6d41\u7a0b\u6a21\u62df<\/h4>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><span>15<\/span><span>16<\/span><span>17<\/span><span>18<\/span><span>19<\/span><span>20<\/span><span>21<\/span><span>22<\/span><span>23<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\"># \u5f53\u4f60\u5199\u4e0b\u8fd9\u6bb5\u4ee3\u7801\u65f6\uff1a\nwith EXPR as VAR:\n    BLOCK\n\n# Python \u89e3\u91ca\u5668\u5728\u5e95\u5c42\u5b9e\u9645\u6267\u884c\u7684\u662f\uff1a\nmanager = EXPR\nenter = type(manager).__enter__\nexit = type(manager).__exit__\nvalue = enter(manager)\nhit_except = False\n\ntry:\n    VAR = value\n    BLOCK  # \u6267\u884c\u4f60\u7684\u4ee3\u7801\u5757\nexcept:\n    hit_except = True\n    # \u5982\u679c __exit__ \u8fd4\u56de False\uff0c\u5f02\u5e38\u4f1a\u7ee7\u7eed\u5411\u5916\u629b\u51fa\n    if not exit(manager, *sys.exc_info()):\n        raise\nfinally:\n    # \u5982\u679c\u6ca1\u6709\u53d1\u751f\u5f02\u5e38\uff0c\u4e5f\u4f1a\u8c03\u7528 __exit__\uff0c\u4e14\u4e09\u4e2a\u53c2\u6570\u5747\u4e3a None\n    if not hit_except:\n        exit(manager, None, None, None)<\/code><\/pre><\/div><\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e09\u3001 \u81ea\u5b9a\u4e49\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u867d\u7136 Python \u63d0\u4f9b\u4e86\u8bb8\u591a\u5185\u7f6e\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\uff08\u5982 <code>open<\/code>\uff09\uff0c\u4f46\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\uff0c\u6211\u4eec\u7ecf\u5e38\u9700\u8981\u4e3a\u81ea\u5df1\u7684\u8d44\u6e90\uff08\u5982\u81ea\u5b9a\u4e49\u6570\u636e\u5e93\u8fde\u63a5\u6c60\u3001\u4e34\u65f6\u76ee\u5f55\u3001\u6027\u80fd\u8ba1\u65f6\u5668\uff09\u7f16\u5199\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u3002\u6709\u4e24\u79cd\u4e3b\u8981\u65b9\u5f0f\uff1a<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">\u65b9\u5f0f 1\uff1a\u57fa\u4e8e\u7c7b (Class-based) \ud83c\udf1f<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u662f\u6700\u6807\u51c6\u3001\u6700\u7075\u6d3b\u7684\u65b9\u5f0f\uff0c\u9002\u5408\u9700\u8981\u7ef4\u62a4\u590d\u6742\u72b6\u6001\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><span>15<\/span><span>16<\/span><span>17<\/span><span>18<\/span><span>19<\/span><span>20<\/span><span>21<\/span><span>22<\/span><span>23<\/span><span>24<\/span><span>25<\/span><span>26<\/span><span>27<\/span><span>28<\/span><span>29<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">import time\n\nclass Timer:\n    def __init__(self, name=&quot;Operation&quot;):\n        self.name = name\n\n    def __enter__(self):\n        self.start_time = time.perf_counter()\n        print(f&quot;[{self.name}] \u5f00\u59cb\u6267\u884c...&quot;)\n        return self  # \u8fd4\u56de self\uff0c\u4ee5\u4fbf\u5728 with \u5757\u4e2d\u4f7f\u7528\n\n    def __exit__(self, exc_type, exc_val, exc_tb):\n        self.end_time = time.perf_counter()\n        elapsed = self.end_time - self.start_time\n        print(f&quot;[{self.name}] \u6267\u884c\u5b8c\u6bd5\uff0c\u8017\u65f6: {elapsed:.4f} \u79d2&quot;)\n\n        # \u5982\u679c\u53d1\u751f\u5f02\u5e38\uff0c\u53ef\u4ee5\u5728\u8fd9\u91cc\u8bb0\u5f55\u65e5\u5fd7\n        if exc_type is not None:\n            print(f&quot;[{self.name}] \u53d1\u751f\u5f02\u5e38: {exc_val}&quot;)\n\n        # \u8fd4\u56de False\uff0c\u8ba9\u5f02\u5e38\u6b63\u5e38\u5411\u5916\u629b\u51fa\n        return False\n\n# \u4f7f\u7528\u81ea\u5b9a\u4e49\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\nwith Timer(&quot;\u6570\u636e\u5904\u7406&quot;) as timer:\n    time.sleep(1)\n    print(&quot;\u6b63\u5728\u5904\u7406\u6570\u636e...&quot;)\n    # \u5982\u679c\u53d6\u6d88\u4e0b\u4e00\u884c\u7684\u6ce8\u91ca\uff0c\u5f02\u5e38\u4f1a\u88ab __exit__ \u6355\u83b7\u5e76\u6253\u5370\uff0c\u7136\u540e\u7ee7\u7eed\u5411\u5916\u629b\u51fa\n    # raise ValueError(&quot;\u6a21\u62df\u9519\u8bef&quot;)<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">\u65b9\u5f0f 2\uff1a\u57fa\u4e8e\u751f\u6210\u5668\u548c <code>@contextmanager<\/code> \u88c5\u9970\u5668<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5bf9\u4e8e\u7b80\u5355\u7684\u8d44\u6e90\u7ba1\u7406\uff0c\u7f16\u5199\u5b8c\u6574\u7684\u7c7b\u663e\u5f97\u8fc7\u4e8e\u7b28\u91cd\u3002Python \u7684 <code>contextlib<\/code> \u6a21\u5757\u63d0\u4f9b\u4e86\u4e00\u4e2a\u88c5\u9970\u5668\uff0c\u5141\u8bb8\u4f60<strong>\u7528\u751f\u6210\u5668\u51fd\u6570\u6765\u5b9a\u4e49\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668<\/strong>\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><code>yield<\/code> <strong>\u4e4b\u524d<\/strong>\u7684\u4ee3\u7801\u76f8\u5f53\u4e8e <code>__enter__<\/code>\u3002<\/li>\n\n\n\n<li><code>yield<\/code> <strong>\u4e4b\u540e<\/strong>\u7684\u4ee3\u7801\u76f8\u5f53\u4e8e <code>__exit__<\/code>\uff08\u5fc5\u987b\u653e\u5728 <code>try...finally<\/code> \u5757\u4e2d\u4ee5\u786e\u4fdd\u6267\u884c\uff09\u3002<\/li>\n\n\n\n<li><code>yield<\/code> \u4ea7\u51fa\u7684\u503c\u5c06\u7ed1\u5b9a\u5230 <code>as<\/code> \u53d8\u91cf\u3002<\/li>\n<\/ul>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><span>15<\/span><span>16<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from contextlib import contextmanager\n\n@contextmanager\ndef managed_file(filename, mode):\n    print(f&quot;\u6b63\u5728\u6253\u5f00\u6587\u4ef6: {filename}&quot;)\n    f = open(filename, mode)\n    try:\n        # yield \u7684\u503c\u5c06\u8d4b\u7ed9 as \u540e\u9762\u7684\u53d8\u91cf\n        yield f\n    finally:\n        print(f&quot;\u6b63\u5728\u5173\u95ed\u6587\u4ef6: {filename}&quot;)\n        f.close()\n\n# \u4f7f\u7528\u65b9\u5f0f\u4e0e\u5185\u7f6e\u7684 open \u5b8c\u5168\u4e00\u81f4\nwith managed_file(&quot;test.txt&quot;, &quot;w&quot;) as f:\n    f.write(&quot;Hello from contextmanager!&quot;)<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\ud83d\udca1 \u63d0\u793a<\/em>\uff1a<code>@contextmanager<\/code> \u6781\u5927\u5730\u7b80\u5316\u4e86\u4ee3\u7801\uff0c\u4f46\u5982\u679c\u9700\u8981\u5728 <code>__exit__<\/code> \u4e2d\u5904\u7406\u590d\u6742\u7684\u5f02\u5e38\u903b\u8f91\uff08\u5982\u6839\u636e\u5f02\u5e38\u7c7b\u578b\u51b3\u5b9a\u662f\u5426\u541e\u6389\u5f02\u5e38\uff09\uff0c\u57fa\u4e8e\u7c7b\u7684\u65b9\u5f0f\u4ecd\u7136\u662f\u66f4\u597d\u7684\u9009\u62e9\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u56db\u3001 Python \u6807\u51c6\u5e93\u5229\u5668\uff1a<code>contextlib<\/code> \u6a21\u5757<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><code>contextlib<\/code> \u662f Python \u6807\u51c6\u5e93\u4e2d\u4e13\u95e8\u7528\u4e8e\u7b80\u5316\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u521b\u5efa\u548c\u4f7f\u7528\u7684\u6a21\u5757\u3002\u9664\u4e86\u4e0a\u8ff0\u7684 <code>@contextmanager<\/code>\uff0c\u5b83\u8fd8\u63d0\u4f9b\u4e86\u8bb8\u591a\u5f00\u7bb1\u5373\u7528\u7684\u5b9e\u7528\u5de5\u5177\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1. <code>contextlib.closing<\/code><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u7528\u4e8e\u90a3\u4e9b<strong>\u6709 <code>close()<\/code> \u65b9\u6cd5\uff0c\u4f46\u6ca1\u6709\u5b9e\u73b0\u5b8c\u6574\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u534f\u8bae<\/strong>\u7684\u65e7\u5f0f\u5bf9\u8c61\uff08\u5982\u67d0\u4e9b\u7b2c\u4e09\u65b9\u5e93\u7684\u6570\u636e\u5e93\u8fde\u63a5\u6216\u7f51\u7edc\u54cd\u5e94\uff09\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from contextlib import closing\nimport urllib.request\n\n# urllib.request.urlopen \u8fd4\u56de\u7684\u5bf9\u8c61\u6709 close() \u65b9\u6cd5\uff0c\u4f46\u5728\u67d0\u4e9b\u65e7\u7248\u672c\u4e2d\u4e0d\u662f\u5b8c\u7f8e\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\nwith closing(urllib.request.urlopen(&#039;https:\/\/www.python.org&#039;)) as page:\n    for line in page:\n        print(line.decode(&#039;utf-8&#039;))\n# \u79bb\u5f00 with \u5757\u65f6\uff0cclosing \u4f1a\u81ea\u52a8\u8c03\u7528 page.close()<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">2. <code>contextlib.suppress<\/code><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f53\u4f60\u660e\u786e\u77e5\u9053\u67d0\u6bb5\u4ee3\u7801\u53ef\u80fd\u4f1a\u629b\u51fa\u7279\u5b9a\u7684\u5f02\u5e38\uff0c\u5e76\u4e14\u4f60<strong>\u5e0c\u671b\u5b89\u5168\u5730\u5ffd\u7565\u5b83<\/strong>\u65f6\uff0c\u4f7f\u7528 <code>suppress<\/code> \u6bd4\u5199\u7a7a\u7684 <code>except<\/code> \u5757\u66f4\u4f18\u96c5\u3001\u66f4\u5177\u58f0\u660e\u6027\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">import os\n\nfilename = &quot;temp_file.txt&quot;\n\n# \u274c \u4f20\u7edf\u5199\u6cd5\uff1a\u7a7a\u7684 except \u5757\u5bb9\u6613\u88ab\u8bef\u8ba4\u4e3a\u662f\u9057\u6f0f\u4e86\u5904\u7406\u903b\u8f91\ntry:\n    os.remove(filename)\nexcept FileNotFoundError:\n    pass\n\n# \u2705 \u63a8\u8350\u5199\u6cd5\uff1a\u6e05\u6670\u8868\u8fbe\u201c\u6211\u5c31\u662f\u8981\u5ffd\u7565\u8fd9\u4e2a\u7279\u5b9a\u7684\u5f02\u5e38\u201d\nfrom contextlib import suppress\nwith suppress(FileNotFoundError):\n    os.remove(filename)<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">3. <code>contextlib.redirect_stdout<\/code> \/ <code>redirect_stderr<\/code><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e34\u65f6\u91cd\u5b9a\u5411\u6807\u51c6\u8f93\u51fa\u6216\u6807\u51c6\u9519\u8bef\u6d41\u3002\u5728\u6d4b\u8bd5\u6216\u6355\u83b7\u7b2c\u4e09\u65b9\u5e93\u7684\u6253\u5370\u8f93\u51fa\u65f6\u975e\u5e38\u6709\u7528\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">import io\nfrom contextlib import redirect_stdout\n\n# \u6355\u83b7 print \u7684\u8f93\u51fa\nf = io.StringIO()\nwith redirect_stdout(f):\n    print(&quot;\u8fd9\u6bb5\u6587\u5b57\u4e0d\u4f1a\u6253\u5370\u5230\u63a7\u5236\u53f0\uff0c\u800c\u662f\u8fdb\u5165\u4e86 StringIO&quot;)\n\noutput = f.getvalue()\nprint(f&quot;\u6355\u83b7\u5230\u7684\u5185\u5bb9: {repr(output)}&quot;)  # &#039;\u8fd9\u6bb5\u6587\u5b57\u4e0d\u4f1a\u6253\u5370\u5230\u63a7\u5236\u53f0\uff0c\u800c\u662f\u8fdb\u5165\u4e86 StringIO\\n&#039;<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">4. <code>contextlib.ExitStack<\/code> (\u52a8\u6001\u8d44\u6e90\u7ba1\u7406\u7684\u795e\u5668) \ud83c\udf1f<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f53\u4f60\u9700\u8981\u7ba1\u7406<strong>\u6570\u91cf\u672a\u77e5<\/strong>\u6216<strong>\u52a8\u6001\u751f\u6210<\/strong>\u7684\u591a\u4e2a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u65f6\uff0c\u5d4c\u5957\u591a\u4e2a <code>with<\/code> \u8bed\u53e5\u4f1a\u5bfc\u81f4\u4ee3\u7801\u5411\u53f3\u65e0\u9650\u5ef6\u4f38\uff08\u201c\u5384\u8fd0\u91d1\u5b57\u5854\u201d\uff09\u3002<code>ExitStack<\/code> \u5141\u8bb8\u4f60\u5728\u8fd0\u884c\u65f6\u52a8\u6001\u5730\u201c\u538b\u5165\u201d (enter) \u591a\u4e2a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\uff0c\u5e76\u5728\u9000\u51fa\u65f6<strong>\u6309\u76f8\u53cd\u7684\u987a\u5e8f<\/strong>\u81ea\u52a8\u6e05\u7406\u5b83\u4eec\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><span>9<\/span><span>10<\/span><span>11<\/span><span>12<\/span><span>13<\/span><span>14<\/span><span>15<\/span><span>16<\/span><span>17<\/span><span>18<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from contextlib import ExitStack\n\nfilenames = [&quot;file1.txt&quot;, &quot;file2.txt&quot;, &quot;file3.txt&quot;]\n\n# \u274c \u4f20\u7edf\u5199\u6cd5\uff1a\u5982\u679c filenames \u6709 100 \u4e2a\uff0c\u4ee3\u7801\u5c06\u65e0\u6cd5\u7f16\u5199\n# with open(filenames[0]) as f0, open(filenames[1]) as f1 ...\n\n# \u2705 \u63a8\u8350\u5199\u6cd5\uff1a\u4f7f\u7528 ExitStack\nwith ExitStack() as stack:\n    # \u52a8\u6001\u6253\u5f00\u6240\u6709\u6587\u4ef6\uff0c\u5e76\u5c06\u6587\u4ef6\u5bf9\u8c61\u4fdd\u5b58\u5728\u5217\u8868\u4e2d\n    files = [stack.enter_context(open(fname, &#039;w&#039;)) for fname in filenames]\n\n    # \u73b0\u5728\u53ef\u4ee5\u5b89\u5168\u5730\u64cd\u4f5c\u6240\u6709\u6587\u4ef6\n    for f in files:\n        f.write(&quot;Data\\n&quot;)\n\n# \u79bb\u5f00 with \u5757\u65f6\uff0cExitStack \u4f1a\u81ea\u52a8\u3001\u5b89\u5168\u5730\u6309\u9006\u5e8f\u5173\u95ed\u6240\u6709\u6253\u5f00\u7684\u6587\u4ef6\u3002\n# \u5373\u4f7f\u5728\u6253\u5f00 file2.txt \u65f6\u53d1\u751f\u5f02\u5e38\uff0cfile1.txt \u4e5f\u4f1a\u88ab\u6b63\u786e\u5173\u95ed\u3002<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\u5e94\u7528\u573a\u666f<\/em>\uff1a\u6279\u91cf\u5904\u7406\u6587\u4ef6\u3001\u7ba1\u7406\u591a\u4e2a\u6570\u636e\u5e93\u4e8b\u52a1\u3001\u52a8\u6001\u52a0\u8f7d\u591a\u4e2a\u63d2\u4ef6\u8d44\u6e90\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e94\u3001 \u9ad8\u7ea7\u7528\u6cd5\uff1a\u5d4c\u5957\u4e0e\u591a\u4e2a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u5728\u4e00\u884c\u4e2d\u7ba1\u7406\u591a\u4e2a\u8d44\u6e90<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4ece Python 2.7 \/ 3.1 \u5f00\u59cb\uff0c<code>with<\/code> \u8bed\u53e5\u652f\u6301\u540c\u65f6\u7ba1\u7406\u591a\u4e2a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\uff0c\u7528\u9017\u53f7\u5206\u9694\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\"># \u540c\u65f6\u6253\u5f00\u4e24\u4e2a\u6587\u4ef6\uff0c\u4e00\u4e2a\u8bfb\uff0c\u4e00\u4e2a\u5199\nwith open(&quot;input.txt&quot;, &quot;r&quot;) as infile, open(&quot;output.txt&quot;, &quot;w&quot;) as outfile:\n    data = infile.read()\n    outfile.write(data.upper())<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\u6ce8\u610f<\/em>\uff1a\u5982\u679c\u524d\u4e00\u4e2a\u7ba1\u7406\u5668\u5728 <code>__enter__<\/code> \u9636\u6bb5\u5931\u8d25\uff0c\u540e\u7eed\u7684\u7ba1\u7406\u5668\u4e0d\u4f1a\u88ab\u6267\u884c\uff1b\u5982\u679c\u540e\u4e00\u4e2a\u5931\u8d25\uff0c\u524d\u4e00\u4e2a\u7684 <code>__exit__<\/code> \u4ecd\u4f1a\u88ab\u6b63\u786e\u8c03\u7528\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u7684\u5d4c\u5957 (Python 3.10+ \u7684\u6539\u8fdb)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728 Python 3.10 \u4e4b\u524d\uff0c\u5982\u679c\u4f60\u9700\u8981\u5c06\u591a\u4e2a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u653e\u5728\u62ec\u53f7\u5185\u6362\u884c\uff0c\u8bed\u6cd5\u4f1a\u6bd4\u8f83\u522b\u626d\u3002Python 3.10 (PEP 617 \u65b0\u7684\u89e3\u6790\u5668) \u4f7f\u5f97\u5e26\u62ec\u53f7\u7684\u591a\u4e2a\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u66f4\u52a0\u81ea\u7136\uff1a<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">with (\n    open(&quot;file1.txt&quot;, &quot;r&quot;) as f1,\n    open(&quot;file2.txt&quot;, &quot;r&quot;) as f2,\n    Timer(&quot;Process&quot;) as timer\n):\n    # \u6267\u884c\u64cd\u4f5c\n    pass<\/code><\/pre><\/div><\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u516d\u3001 \u6838\u5fc3\u5e94\u7528\u573a\u666f\u76d8\u70b9<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u6587\u4ef6\u64cd\u4f5c<\/strong>\uff1a<code>with open(...) as f:<\/code> (\u6700\u7ecf\u5178\u573a\u666f)\u3002<\/li>\n\n\n\n<li><strong>\u7ebf\u7a0b\/\u5f02\u6b65\u9501<\/strong>\uff1a<code>with threading.Lock():<\/code> \u6216 <code>async with asyncio.Lock():<\/code>\uff0c\u786e\u4fdd\u4e34\u754c\u533a\u4ee3\u7801\u6267\u884c\u540e\u5fc5\u5b9a\u91ca\u653e\u9501\uff0c\u9632\u6b62\u6b7b\u9501\u3002<\/li>\n\n\n\n<li><strong>\u6570\u636e\u5e93\u4e8b\u52a1<\/strong>\uff1a\u8bb8\u591a\u6570\u636e\u5e93\u9a71\u52a8\uff08\u5982 <code>sqlite3<\/code>, <code>SQLAlchemy<\/code>\uff09\u652f\u6301 <code>with<\/code>\uff0c\u7528\u4e8e\u81ea\u52a8 <code>commit<\/code> \u6216\u5728\u5f02\u5e38\u65f6 <code>rollback<\/code>\u3002<\/li>\n<\/ol>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">   import sqlite3\n   conn = sqlite3.connect(&quot;test.db&quot;)\n   with conn:  # \u8fd9\u91cc\u7684 with \u7ba1\u7406\u7684\u662f\u4e8b\u52a1\uff0c\u800c\u4e0d\u662f\u8fde\u63a5\u672c\u8eab\n       conn.execute(&quot;INSERT INTO users (name) VALUES (?)&quot;, (&quot;Alice&quot;,))\n   # \u79bb\u5f00\u5757\u65f6\u81ea\u52a8 commit\uff0c\u5982\u679c\u53d1\u751f\u5f02\u5e38\u5219\u81ea\u52a8 rollback<\/code><\/pre><\/div><\/div>\n\n\n\n<ol start=\"4\" class=\"wp-block-list\">\n<li><strong>\u4e34\u65f6\u4fee\u6539\u73af\u5883\u72b6\u6001<\/strong>\uff1a\u5982\u4e34\u65f6\u5207\u6362\u5de5\u4f5c\u76ee\u5f55\u3001\u4e34\u65f6\u4fee\u6539\u7cfb\u7edf\u73af\u5883\u53d8\u91cf\uff0c\u9000\u51fa\u65f6\u81ea\u52a8\u6062\u590d\u3002<\/li>\n\n\n\n<li><strong>\u6027\u80fd\u5256\u6790\u4e0e\u8ba1\u65f6<\/strong>\uff1a\u5982\u524d\u6587\u81ea\u5b9a\u4e49\u7684 <code>Timer<\/code> \u7c7b\u3002<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u4e03\u3001 \u6838\u5fc3\u907f\u5751\u6307\u5357\u4e0e\u6700\u4f73\u5b9e\u8df5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u26a0\ufe0f \u9677\u9631\uff1a<code>with<\/code> \u5757\u5185\u7684\u53d8\u91cf\u4f5c\u7528\u57df<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e0e\u67d0\u4e9b\u8bed\u8a00\uff08\u5982 C++ \u7684\u5757\u7ea7\u4f5c\u7528\u57df\uff09\u4e0d\u540c\uff0c<strong>\u5728 <code>with<\/code> \u5757\u5185\u90e8\u8d4b\u503c\u7684\u53d8\u91cf\uff0c\u5728\u5757\u5916\u90e8\u4f9d\u7136\u53ef\u89c1\u4e14\u53ef\u7528<\/strong>\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">with open(&quot;test.txt&quot;, &quot;w&quot;) as f:\n    f.write(&quot;data&quot;)\n    my_var = &quot;I am inside with&quot;\n\nprint(my_var)  # \u8f93\u51fa: &quot;I am inside with&quot; (\u53d8\u91cf\u5e76\u672a\u88ab\u9500\u6bc1)<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\u6ce8\u610f<\/em>\uff1a\u867d\u7136\u53d8\u91cf\u53ef\u89c1\uff0c\u4f46\u5982\u679c\u8be5\u53d8\u91cf\u5f15\u7528\u7684\u662f <code>with<\/code> \u7ba1\u7406\u7684\u8d44\u6e90\uff08\u5982\u6587\u4ef6\u5bf9\u8c61 <code>f<\/code>\uff09\uff0c\u5728\u5757\u5916\u90e8\u5c1d\u8bd5\u4f7f\u7528\u5b83\u5c06\u4f1a\u5bfc\u81f4\u9519\u8bef\uff08\u5982 <code>ValueError: I\/O operation on closed file<\/code>\uff09\uff0c\u56e0\u4e3a\u8d44\u6e90\u5df2\u7ecf\u88ab <code>__exit__<\/code> \u6e05\u7406\u4e86\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u26a0\ufe0f \u9677\u9631\uff1a<code>__exit__<\/code> \u4e2d\u7684\u5f02\u5e38\u5904\u7406\u903b\u8f91<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u4f60\u5728\u81ea\u5b9a\u4e49\u7c7b\u7684 <code>__exit__<\/code> \u4e2d\u5904\u7406\u5f02\u5e38\uff0c<strong>\u52a1\u5fc5\u5c0f\u5fc3\u8fd4\u56de\u503c<\/strong>\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><span>6<\/span><span>7<\/span><span>8<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">class BadManager:\n    def __enter__(self): return self\n    def __exit__(self, exc_type, exc_val, exc_tb):\n        print(&quot;Cleaning up...&quot;)\n        return True  # \u26a0\ufe0f \u5371\u9669\uff01\u8fd9\u4f1a\u541e\u6389 with \u5757\u5185\u53d1\u751f\u7684\u6240\u6709\u5f02\u5e38\uff01\n\nwith BadManager():\n    raise ValueError(&quot;\u8fd9\u4e2a\u9519\u8bef\u5c06\u88ab\u9759\u9ed8\u541e\u6389\uff0c\u6781\u96be\u8c03\u8bd5\uff01&quot;)<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\u6700\u4f73\u5b9e\u8df5<\/em>\uff1a\u9664\u975e\u4f60\u660e\u786e\u8bbe\u8ba1\u4e86\u4e00\u4e2a\u201c\u5f02\u5e38\u6291\u5236\u5668\u201d\uff08\u5982 <code>contextlib.suppress<\/code>\uff09\uff0c\u5426\u5219 <code>__exit__<\/code> \u5e94\u8be5\u59cb\u7ec8\u8fd4\u56de <code>False<\/code> \u6216 <code>None<\/code>\uff0c\u8ba9\u5f02\u5e38\u6b63\u5e38\u4f20\u64ad\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">3. \u26a0\ufe0f \u9677\u9631\uff1a\u4e0d\u8981\u5c06 <code>with<\/code> \u7528\u4e8e\u4e0d\u9700\u8981\u6e05\u7406\u7684\u8d44\u6e90<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><code>with<\/code> \u7684\u76ee\u7684\u662f<strong>\u8d44\u6e90\u7ba1\u7406<\/strong>\u3002\u5982\u679c\u4e00\u4e2a\u64cd\u4f5c\u4ec5\u4ec5\u662f\u666e\u901a\u7684\u51fd\u6570\u8c03\u7528\uff0c\u6ca1\u6709\u9700\u8981\u6e05\u7406\u7684\u72b6\u6001\uff0c\u5f3a\u884c\u5305\u88c5\u6210\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u662f\u53cd\u6a21\u5f0f\u3002<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\"># \u274c \u53cd\u6a21\u5f0f\uff1aprint \u4e0d\u9700\u8981\u6e05\u7406\n# with print(&quot;Hello&quot;): pass \n\n# \u2705 \u6b63\u786e\uff1a\u76f4\u63a5\u8c03\u7528\nprint(&quot;Hello&quot;)<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">4. \ud83d\udca1 \u6700\u4f73\u5b9e\u8df5\uff1a\u4f18\u5148\u4f7f\u7528\u6807\u51c6\u5e93\u6216\u7b2c\u4e09\u65b9\u5e93\u63d0\u4f9b\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u5c1d\u8bd5\u81ea\u5df1\u5199 <code>__enter__<\/code> \u548c <code>__exit__<\/code> \u4e4b\u524d\uff0c\u5148\u68c0\u67e5 <code>contextlib<\/code> \u6216\u76f8\u5173\u5e93\u662f\u5426\u5df2\u7ecf\u63d0\u4f9b\u4e86\u73b0\u6210\u7684\u89e3\u51b3\u65b9\u6848\u3002\u4f8b\u5982\uff0c\u5904\u7406 HTTP \u8bf7\u6c42\u65f6\uff0c<code>requests<\/code> \u5e93\u7684 <code>Session<\/code> \u5bf9\u8c61\u5c31\u662f\u4e00\u4e2a\u4f18\u79c0\u7684\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\uff1a<\/p>\n\n\n\n<div class=\"chp-code-block chp-theme-github-dark chp-wrap-on\" data-chp-language=\"plaintext\" data-chp-line-start=\"1\" data-chp-highlight=\"\"><div class=\"chp-toolbar\"><div class=\"chp-toolbar-left\"><span class=\"chp-dots\"><span><\/span><span><\/span><span><\/span><\/span><span class=\"chp-language-label\">\u7eaf\u6587\u672c<\/span><\/div><div class=\"chp-toolbar-right\"><button type=\"button\" class=\"chp-copy-btn\" aria-label=\"\u590d\u5236\u4ee3\u7801\"><svg class=\"chp-icon-copy\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\"><path fill=\"currentColor\" d=\"M16 1H4c-1.1 0-2 .9-2 2v14h2V3h12V1zm3 4H8c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h11c1.1 0 2-.9 2-2V7c0-1.1-.9-2-2-2zm0 16H8V7h11v14z\"\/><\/svg><svg class=\"chp-icon-check\" viewBox=\"0 0 24 24\" width=\"14\" height=\"14\" aria-hidden=\"true\" style=\"display:none;\"><path fill=\"currentColor\" d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"\/><\/svg><span class=\"chp-copy-text\">\u590d\u5236<\/span><\/button><\/div><\/div><div class=\"chp-code-wrapper\"><div class=\"chp-line-numbers\" aria-hidden=\"true\"><span>1<\/span><span>2<\/span><span>3<\/span><span>4<\/span><span>5<\/span><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">import requests\n\nwith requests.Session() as session:\n    # Session \u4f1a\u5728\u9000\u51fa\u65f6\u81ea\u52a8\u5173\u95ed\u5e95\u5c42\u7684\u8fde\u63a5\u6c60\n    response = session.get(&quot;https:\/\/api.github.com&quot;)<\/code><\/pre><\/div><\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u516b\u3001 \u603b\u7ed3<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Python \u7684 <code>with<\/code> \u5173\u952e\u5b57\u548c\u4e0a\u4e0b\u6587\u7ba1\u7406\u5668\u534f\u8bae\uff0c\u662f Python \u5b9e\u73b0 <strong>RAII (Resource Acquisition Is Initialization)<\/strong> \u7406\u5ff5\u7684\u4f18\u96c5\u4f53\u73b0\u3002<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u5b89\u5168\u6027<\/strong>\uff1a\u5b83\u901a\u8fc7\u5f3a\u5236\u7684 <code>__exit__<\/code> \u8c03\u7528\uff0c\u5f7b\u5e95\u6d88\u706d\u4e86\u56e0\u9057\u5fd8\u91ca\u653e\u8d44\u6e90\u800c\u5bfc\u81f4\u7684\u5185\u5b58\u6cc4\u6f0f\u3001\u6587\u4ef6\u63cf\u8ff0\u7b26\u8017\u5c3d\u6216\u6b7b\u9501\u95ee\u9898\u3002<\/li>\n\n\n\n<li><strong>\u7b80\u6d01\u6027<\/strong>\uff1a\u5b83\u5c06\u590d\u6742\u7684 <code>try...finally<\/code> \u6837\u677f\u4ee3\u7801\u538b\u7f29\u4e3a\u4e00\u884c\u58f0\u660e\u5f0f\u8bed\u6cd5\uff0c\u6781\u5927\u63d0\u5347\u4e86\u4ee3\u7801\u7684\u53ef\u8bfb\u6027\u3002<\/li>\n\n\n\n<li><strong>\u6269\u5c55\u6027<\/strong>\uff1a\u901a\u8fc7 <code>contextlib<\/code> \u6a21\u5757\uff08\u5c24\u5176\u662f <code>@contextmanager<\/code> \u548c <code>ExitStack<\/code>\uff09\uff0c\u5f00\u53d1\u8005\u53ef\u4ee5\u4ee5\u6781\u4f4e\u7684\u6210\u672c\u4e3a\u4efb\u4f55\u81ea\u5b9a\u4e49\u903b\u8f91\u8d4b\u4e88\u4e0a\u4e0b\u6587\u7ba1\u7406\u80fd\u529b\u3002<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u73b0\u4ee3 Python \u5f00\u53d1\u4e2d\uff0c<strong>\u201c\u53ea\u8981\u6d89\u53ca\u8d44\u6e90\u7684\u83b7\u53d6\u4e0e\u91ca\u653e\uff0c\u5c31\u5e94\u5f53\u4f18\u5148\u8003\u8651\u4f7f\u7528 <code>with<\/code>\u201d<\/strong> \u5df2\u7ecf\u6210\u4e3a\u4e00\u6761\u94c1\u5f8b\u3002\u719f\u7ec3\u638c\u63e1\u5b83\uff0c\u662f\u4f60\u5199\u51fa\u5065\u58ee\u3001\u4e13\u4e1a\u3001Pythonic \u4ee3\u7801\u7684\u91cd\u8981\u91cc\u7a0b\u7891\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u4f60\u5bf9 <code>with<\/code> \u5728\u5f02\u6b65\u7f16\u7a0b (<code>async with<\/code>) \u4e2d\u7684\u5e94\u7528\uff0c\u6216\u8005\u5982\u4f55\u5229\u7528 <code>ExitStack<\/code> \u6784\u5efa\u590d\u6742\u7684\u5fae\u670d\u52a1\u8d44\u6e90\u7f16\u6392\u903b\u8f91\u6709\u8fdb\u4e00\u6b65\u7684\u7591\u95ee\uff0c\u6b22\u8fce\u968f\u65f6\u6df1\u5165\u63a2\u8ba8\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728 Python 3 \u4e2d\uff0cwith \u5173\u952e\u5b57\uff08\u914d\u5408\u4e0a&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-70","post","type-post","status-publish","format-standard","hentry","category-python-3-"],"_links":{"self":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/70","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/comments?post=70"}],"version-history":[{"count":1,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/70\/revisions"}],"predecessor-version":[{"id":71,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/posts\/70\/revisions\/71"}],"wp:attachment":[{"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/media?parent=70"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/categories?post=70"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.52runoob.com\/index.php\/wp-json\/wp\/v2\/tags?post=70"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}