{"id":56,"date":"2026-06-13T16:40:42","date_gmt":"2026-06-13T08:40:42","guid":{"rendered":"https:\/\/www.52runoob.com\/?p=56"},"modified":"2026-06-13T16:40:42","modified_gmt":"2026-06-13T08:40:42","slug":"python3-%e5%ad%97%e5%85%b8","status":"publish","type":"post","link":"https:\/\/www.52runoob.com\/index.php\/2026\/06\/13\/python3-%e5%ad%97%e5%85%b8\/","title":{"rendered":"Python3\u00a0\u5b57\u5178"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\u5728 Python 3 \u4e2d\uff0c<strong>\u5b57\u5178 (Dictionary, <code>dict<\/code>)<\/strong> \u662f\u6700\u6838\u5fc3\u3001\u6700\u5f3a\u5927\u7684\u5185\u7f6e\u6570\u636e\u7ed3\u6784\u4e4b\u4e00\u3002\u5b83\u901a\u8fc7<strong>\u952e\u503c\u5bf9 (Key-Value pairs)<\/strong> \u7684\u5f62\u5f0f\u5b58\u50a8\u6570\u636e\uff0c\u5e95\u5c42\u57fa\u4e8e\u9ad8\u5ea6\u4f18\u5316\u7684<strong>\u54c8\u5e0c\u8868 (Hash Table)<\/strong> \u5b9e\u73b0\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5b57\u5178\u4e0d\u4ec5\u662f Python \u5f00\u53d1\u8005\u65e5\u5e38\u4f7f\u7528\u6700\u9891\u7e41\u7684\u5de5\u5177\uff0c\u4e5f\u662f\u7406\u89e3 Python \u5bf9\u8c61\u6a21\u578b\u3001\u547d\u540d\u7a7a\u95f4\uff08\u5982 <code>globals()<\/code> \u548c <code>locals()<\/code>\uff09\u4ee5\u53ca\u73b0\u4ee3 Python \u6027\u80fd\u4f18\u5316\u7684\u5173\u952e\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4ee5\u4e0b\u662f\u5bf9 Python 3 \u5b57\u5178\u7684\u5168\u9762\u3001\u6df1\u5ea6\u89e3\u6790\uff0c\u6db5\u76d6\u4ece\u57fa\u7840\u8bed\u6cd5\u3001\u9ad8\u7ea7\u7279\u6027\u3001\u5e95\u5c42\u539f\u7406\u5230\u6700\u4f73\u5b9e\u8df5\u7684\u5b8c\u6574\u6307\u5357\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 \u5b57\u5178\u7684\u6838\u5fc3\u7279\u6027<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u952e\u503c\u5bf9\u6620\u5c04<\/strong>\uff1a\u901a\u8fc7\u552f\u4e00\u7684\u201c\u952e (Key)\u201d\u6765\u5feb\u901f\u67e5\u627e\u5bf9\u5e94\u7684\u201c\u503c (Value)\u201d\u3002<\/li>\n\n\n\n<li><strong>\u53ef\u53d8\u6027 (Mutable)<\/strong>\uff1a\u5b57\u5178\u7684\u5185\u5bb9\u53ef\u4ee5\u52a8\u6001\u5730\u589e\u52a0\u3001\u5220\u9664\u6216\u4fee\u6539\u3002<\/li>\n\n\n\n<li><strong>\u952e\u7684\u552f\u4e00\u6027\u4e0e\u53ef\u54c8\u5e0c\u6027 (Hashable)<\/strong>\uff1a\u5b57\u5178\u7684\u952e\u5fc5\u987b\u662f<strong>\u4e0d\u53ef\u53d8\u4e14\u53ef\u54c8\u5e0c<\/strong>\u7684\u7c7b\u578b\uff08\u5982\u5b57\u7b26\u4e32\u3001\u6570\u5b57\u3001\u5143\u7ec4\uff09\u3002\u5217\u8868\u6216\u5b57\u5178\u4e0d\u80fd\u4f5c\u4e3a\u952e\u3002<\/li>\n\n\n\n<li><strong>\u4fdd\u6301\u63d2\u5165\u987a\u5e8f (Ordered)<\/strong>\uff1a<strong>\u4ece Python 3.7 \u5f00\u59cb<\/strong>\uff0c\u5b57\u5178\u6b63\u5f0f\u4fdd\u8bc1\u4fdd\u6301\u5143\u7d20\u7684\u63d2\u5165\u987a\u5e8f\u3002\uff08Python 3.6 \u4e2d\u4f5c\u4e3a CPython \u7684\u5b9e\u73b0\u7ec6\u8282\uff0c3.7 \u5199\u5165\u8bed\u8a00\u89c4\u8303\uff09\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 \u5b57\u5178\u7684\u521b\u5efa\u4e0e\u521d\u59cb\u5316<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u5b57\u9762\u91cf\u521b\u5efa (\u6700\u5e38\u7528\u3001\u6700\u63a8\u8350)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4f7f\u7528\u82b1\u62ec\u53f7 <code>{}<\/code> \u548c\u5192\u53f7 <code>:<\/code>\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\"># \u7a7a\u5b57\u5178\nempty_dict = {}\n\n# \u6807\u51c6\u5b57\u5178\nuser = {\n    &quot;name&quot;: &quot;Alice&quot;,\n    &quot;age&quot;: 28,\n    &quot;is_active&quot;: True\n}\n\n# \u952e\u53ef\u4ee5\u662f\u4e0d\u540c\u7c7b\u578b\u7684\u53ef\u54c8\u5e0c\u5bf9\u8c61\nmixed_keys = {\n    1: &quot;one&quot;,\n    (2, 3): &quot;tuple_key&quot;,  # \u5143\u7ec4\u4f5c\u4e3a\u952e\n    3.14: &quot;pi&quot;\n}<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u4f7f\u7528 <code>dict()<\/code> \u6784\u9020\u51fd\u6570<\/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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\"># \u4ece\u952e\u503c\u5bf9\u5e8f\u5217\uff08\u5982\u5217\u8868\u5305\u542b\u5143\u7ec4\uff09\u521b\u5efa\npairs = [(&quot;name&quot;, &quot;Bob&quot;), (&quot;age&quot;, 30)]\nd1 = dict(pairs)  # {&#039;name&#039;: &#039;Bob&#039;, &#039;age&#039;: 30}\n\n# \u4f7f\u7528\u5173\u952e\u5b57\u53c2\u6570 (\u6ce8\u610f\uff1a\u952e\u5fc5\u987b\u662f\u5408\u6cd5\u7684 Python \u6807\u8bc6\u7b26\uff0c\u4e14\u53ea\u80fd\u662f\u5b57\u7b26\u4e32)\nd2 = dict(name=&quot;Charlie&quot;, age=25)  # {&#039;name&#039;: &#039;Charlie&#039;, &#039;age&#039;: 25}\n\n# \u7ed3\u5408 zip \u51fd\u6570\u5feb\u901f\u521b\u5efa\u5b57\u5178\nkeys = [&quot;a&quot;, &quot;b&quot;, &quot;c&quot;]\nvalues = [1, 2, 3]\nd3 = dict(zip(keys, values))  # {&#039;a&#039;: 1, &#039;b&#039;: 2, &#039;c&#039;: 3}<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">3. \u5b57\u5178\u63a8\u5bfc\u5f0f (Dict Comprehension) \ud83c\udf1f<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e0e\u5217\u8868\u63a8\u5bfc\u5f0f\u7c7b\u4f3c\uff0c\u7528\u4e8e\u57fa\u4e8e\u73b0\u6709\u6570\u636e\u5feb\u901f\u751f\u6210\u65b0\u5b57\u5178\uff0c\u4ee3\u7801\u7b80\u6d01\u4e14\u6267\u884c\u6548\u7387\u9ad8\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\"># \u57fa\u7840\u7528\u6cd5\uff1a\u751f\u6210\u6570\u5b57\u53ca\u5176\u5e73\u65b9\u7684\u6620\u5c04\nsquares = {x: x**2 for x in range(5)}\n# \u7ed3\u679c: {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}\n\n# \u5e26\u6761\u4ef6\u8fc7\u6ee4\uff1a\u53ea\u4fdd\u7559\u5076\u6570\u7684\u5e73\u65b9\neven_squares = {x: x**2 for x in range(10) if x % 2 == 0}\n\n# \u952e\u503c\u53cd\u8f6c (\u4ea4\u6362\u952e\u548c\u503c)\noriginal = {&quot;a&quot;: 1, &quot;b&quot;: 2, &quot;c&quot;: 3}\nreversed_dict = {v: k for k, v in original.items()}\n# \u7ed3\u679c: {1: &#039;a&#039;, 2: &#039;b&#039;, 3: &#039;c&#039;}<\/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 \u5b57\u5178\u7684\u589e\u3001\u5220\u3001\u6539\u3001\u67e5\u64cd\u4f5c<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u67e5\u627e\u4e0e\u8bbf\u95ee (Read)<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><code>d[key]<\/code><\/strong>\uff1a\u76f4\u63a5\u8bbf\u95ee\u3002\u5982\u679c\u952e\u4e0d\u5b58\u5728\uff0c\u4f1a\u629b\u51fa <code>KeyError<\/code>\u3002\u65f6\u95f4\u590d\u6742\u5ea6 $O(1)$\u3002<\/li>\n\n\n\n<li><strong><code>d.get(key, default=None)<\/code><\/strong>\uff1a<strong>\u6700\u63a8\u8350\u7684\u8bbf\u95ee\u65b9\u5f0f<\/strong>\u3002\u5982\u679c\u952e\u5b58\u5728\uff0c\u8fd4\u56de\u503c\uff1b\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u8fd4\u56de <code>default<\/code>\uff08\u9ed8\u8ba4\u4e3a <code>None<\/code>\uff09\uff0c<strong>\u4e0d\u4f1a\u62a5\u9519<\/strong>\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">user = {&quot;name&quot;: &quot;Alice&quot;, &quot;age&quot;: 28}\n\n# \u76f4\u63a5\u8bbf\u95ee\nprint(user[&quot;name&quot;])  # &#039;Alice&#039;\n# print(user[&quot;email&quot;])  # KeyError: &#039;email&#039;\n\n# \u5b89\u5168\u8bbf\u95ee\nprint(user.get(&quot;email&quot;))           # None\nprint(user.get(&quot;email&quot;, &quot;N\/A&quot;))    # &#039;N\/A&#039; (\u63d0\u4f9b\u9ed8\u8ba4\u503c)<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u589e\u52a0\u4e0e\u4fee\u6539 (Update)<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><code>d[key] = value<\/code><\/strong>\uff1a\u5982\u679c <code>key<\/code> \u5b58\u5728\uff0c\u5219<strong>\u4fee\u6539<\/strong>\u5176\u503c\uff1b\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5219<strong>\u65b0\u589e<\/strong>\u952e\u503c\u5bf9\u3002<\/li>\n\n\n\n<li><strong><code>d.setdefault(key, default)<\/code><\/strong>\uff1a\u5982\u679c <code>key<\/code> \u5b58\u5728\uff0c\u8fd4\u56de\u5176\u503c\uff1b\u5982\u679c\u4e0d\u5b58\u5728\uff0c\u5219\u63d2\u5165 <code>key: default<\/code> \u5e76\u8fd4\u56de <code>default<\/code>\u3002<strong>\u8fd9\u662f\u5728\u5b57\u5178\u4e2d\u521d\u59cb\u5316\u5217\u8868\u6216\u96c6\u5408\u7684\u5229\u5668<\/strong>\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\">user = {&quot;name&quot;: &quot;Alice&quot;}\n\n# \u4fee\u6539\/\u65b0\u589e\nuser[&quot;age&quot;] = 28       # \u65b0\u589e\nuser[&quot;name&quot;] = &quot;Bob&quot;   # \u4fee\u6539\n\n# setdefault \u7684\u7ecf\u5178\u5e94\u7528\uff1a\u6309\u7c7b\u522b\u5206\u7ec4\nwords = [&quot;apple&quot;, &quot;bat&quot;, &quot;car&quot;, &quot;ant&quot;, &quot;bear&quot;]\ngrouped = {}\nfor word in words:\n    first_letter = word[0]\n    # \u5982\u679c first_letter \u4e0d\u5b58\u5728\uff0c\u5148\u521d\u59cb\u5316\u4e3a\u7a7a\u5217\u8868\uff0c\u7136\u540e append\n    grouped.setdefault(first_letter, []).append(word)\n\nprint(grouped)  \n# {&#039;a&#039;: [&#039;apple&#039;, &#039;ant&#039;], &#039;b&#039;: [&#039;bat&#039;, &#039;bear&#039;], &#039;c&#039;: [&#039;car&#039;]}<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">3. \u5220\u9664 (Delete)<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong><code>del d[key]<\/code><\/strong>\uff1a\u5220\u9664\u6307\u5b9a\u952e\u503c\u5bf9\u3002\u952e\u4e0d\u5b58\u5728\u65f6\u629b\u51fa <code>KeyError<\/code>\u3002<\/li>\n\n\n\n<li><strong><code>d.pop(key, default)<\/code><\/strong>\uff1a\u5220\u9664\u6307\u5b9a\u952e\u5e76<strong>\u8fd4\u56de\u5176\u503c<\/strong>\u3002\u5982\u679c\u952e\u4e0d\u5b58\u5728\u4e14\u63d0\u4f9b\u4e86 <code>default<\/code>\uff0c\u5219\u8fd4\u56de <code>default<\/code>\uff1b\u5426\u5219\u629b\u51fa <code>KeyError<\/code>\u3002<\/li>\n\n\n\n<li><strong><code>d.popitem()<\/code><\/strong>\uff1a\u5220\u9664\u5e76\u8fd4\u56de<strong>\u6700\u540e\u63d2\u5165<\/strong>\u7684\u952e\u503c\u5bf9\uff08\u4ee5\u5143\u7ec4\u5f62\u5f0f\uff09\u3002\u5982\u679c\u5b57\u5178\u4e3a\u7a7a\uff0c\u629b\u51fa <code>KeyError<\/code>\u3002\uff08\u5728 Python 3.7 \u4e4b\u524d\uff0c\u5b83\u662f\u968f\u673a\u5220\u9664\u7684\uff09\u3002<\/li>\n\n\n\n<li><strong><code>d.clear()<\/code><\/strong>\uff1a\u6e05\u7a7a\u5b57\u5178\u4e2d\u7684\u6240\u6709\u5143\u7d20\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">d = {&quot;a&quot;: 1, &quot;b&quot;: 2, &quot;c&quot;: 3}\n\nval = d.pop(&quot;b&quot;)       # val = 2, d \u53d8\u4e3a {&#039;a&#039;: 1, &#039;c&#039;: 3}\n# d.pop(&quot;z&quot;)           # KeyError\nd.pop(&quot;z&quot;, &quot;Not Found&quot;) # &#039;Not Found&#039; (\u5b89\u5168\u5220\u9664)\n\nlast_item = d.popitem() # last_item = (&#039;c&#039;, 3), d \u53d8\u4e3a {&#039;a&#039;: 1}\n\ndel d[&quot;a&quot;]             # d \u53d8\u4e3a {}\nd.clear()              # \u5f7b\u5e95\u6e05\u7a7a<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">4. \u6279\u91cf\u66f4\u65b0\uff1a<code>d.update()<\/code><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5c06\u53e6\u4e00\u4e2a\u5b57\u5178\u6216\u53ef\u8fed\u4ee3\u7684\u952e\u503c\u5bf9\u5408\u5e76\u5230\u5f53\u524d\u5b57\u5178\u4e2d\u3002\u5df2\u5b58\u5728\u7684\u952e\u4f1a\u88ab\u8986\u76d6\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\">d1 = {&quot;a&quot;: 1, &quot;b&quot;: 2}\nd2 = {&quot;b&quot;: 99, &quot;c&quot;: 3}\n\nd1.update(d2)\nprint(d1)  # {&#039;a&#039;: 1, &#039;b&#039;: 99, &#039;c&#039;: 3}\n\n# \u4e5f\u53ef\u4ee5\u4f7f\u7528\u5173\u952e\u5b57\u53c2\u6570\nd1.update(d=4, e=5)<\/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\">\u56db\u3001 \u5b57\u5178\u7684\u904d\u5386<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u5b57\u5178\u63d0\u4f9b\u4e86\u4e09\u4e2a\u89c6\u56fe\u5bf9\u8c61 (View Objects)\uff1a<code>keys()<\/code>, <code>values()<\/code>, <code>items()<\/code>\u3002\u5b83\u4eec\u52a8\u6001\u53cd\u6620\u5b57\u5178\u7684\u53d8\u5316\uff0c\u4e14\u8fed\u4ee3\u6548\u7387\u6781\u9ad8\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">user = {&quot;name&quot;: &quot;Alice&quot;, &quot;age&quot;: 28, &quot;city&quot;: &quot;NY&quot;}\n\n# 1. \u904d\u5386\u952e (\u9ed8\u8ba4\u884c\u4e3a\uff0c\u7b49\u540c\u4e8e user.keys())\nfor key in user:\n    print(key)\n\n# 2. \u904d\u5386\u503c\nfor value in user.values():\n    print(value)\n\n# 3. \u904d\u5386\u952e\u503c\u5bf9 (\u6700\u5e38\u7528\uff0c\u5229\u7528\u5143\u7ec4\u89e3\u5305)\nfor key, value in user.items():\n    print(f&quot;{key}: {value}&quot;)<\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\">\u26a0\ufe0f <strong>\u6838\u5fc3\u907f\u5751\uff1a\u4e0d\u8981\u5728\u904d\u5386\u5b57\u5178\u65f6\u4fee\u6539\u5176\u5927\u5c0f<\/strong><br>\u5728\u8fed\u4ee3 <code>keys()<\/code>, <code>values()<\/code> \u6216 <code>items()<\/code> \u65f6\uff0c\u5982\u679c\u6dfb\u52a0\u6216\u5220\u9664\u4e86\u5b57\u5178\u7684\u952e\uff0c\u4f1a\u629b\u51fa <code>RuntimeError: dictionary changed size during iteration<\/code>\u3002<br><strong>\u6b63\u786e\u505a\u6cd5<\/strong>\uff1a\u5982\u679c\u8981\u5220\u9664\u5143\u7d20\uff0c\u5148\u5c06\u5176\u952e\u6536\u96c6\u5230\u4e00\u4e2a\u5217\u8868\u4e2d\uff0c\u6216\u8005\u904d\u5386\u5b57\u5178\u7684\u526f\u672c <code>list(d.keys())<\/code> \u6216 <code>d.copy()<\/code>\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\">d = {&quot;a&quot;: 1, &quot;b&quot;: 2, &quot;c&quot;: 3}\n\n# \u274c \u9519\u8bef\u505a\u6cd5\n# for k in d:\n#     if k == &quot;b&quot;:\n#         del d[k]  # RuntimeError\n\n# \u2705 \u6b63\u786e\u505a\u6cd5 1\uff1a\u904d\u5386\u952e\u7684\u5217\u8868\u526f\u672c\nfor k in list(d.keys()):\n    if k == &quot;b&quot;:\n        del d[k]\n\n# \u2705 \u6b63\u786e\u505a\u6cd5 2\uff1a\u4f7f\u7528\u5b57\u5178\u63a8\u5bfc\u5f0f\u521b\u5efa\u65b0\u5b57\u5178 (\u66f4 Pythonic)\nd = {k: v for k, v in d.items() if k != &quot;b&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\">\u4e94\u3001 \u5b57\u5178\u7684\u8fdb\u9636\u7279\u6027\u4e0e\u73b0\u4ee3 Python \u8bed\u6cd5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u5b57\u5178\u5408\u5e76\u8fd0\u7b97\u7b26 <code>|<\/code> \u548c <code>|=<\/code> (Python 3.9+)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u662f Python 3.9 \u5f15\u5165\u7684\u91cd\u5927\u8bed\u6cd5\u7cd6\uff0c\u4f7f\u5f97\u5b57\u5178\u5408\u5e76\u53d8\u5f97\u6781\u5176\u4f18\u96c5\uff0c\u53d6\u4ee3\u4e86\u7e41\u7410\u7684 <code>update()<\/code> \u6216 <code>{**d1, **d2}<\/code>\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\">d1 = {&quot;a&quot;: 1, &quot;b&quot;: 2}\nd2 = {&quot;b&quot;: 99, &quot;c&quot;: 3}\n\n# | \u8fd0\u7b97\u7b26\uff1a\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684\u5408\u5e76\u540e\u7684\u5b57\u5178 (d2 \u7684\u503c\u8986\u76d6 d1 \u7684\u51b2\u7a81\u952e)\nd3 = d1 | d2  \nprint(d3)  # {&#039;a&#039;: 1, &#039;b&#039;: 99, &#039;c&#039;: 3}\n\n# |= \u8fd0\u7b97\u7b26\uff1a\u5c31\u5730\u66f4\u65b0 (In-place update)\uff0c\u7b49\u540c\u4e8e d1.update(d2)\nd1 |= d2\nprint(d1)  # {&#039;a&#039;: 1, &#039;b&#039;: 99, &#039;c&#039;: 3}<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u5b57\u5178\u89e3\u5305 <code>**<\/code><\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u51fd\u6570\u8c03\u7528\u6216\u521b\u5efa\u65b0\u5b57\u5178\u65f6\uff0c\u4f7f\u7528 <code>**<\/code> \u53ef\u4ee5\u89e3\u5305\u5b57\u5178\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">defaults = {&quot;host&quot;: &quot;localhost&quot;, &quot;port&quot;: 8080}\noverrides = {&quot;port&quot;: 9000, &quot;timeout&quot;: 30}\n\n# \u5408\u5e76\u5b57\u5178 (\u65e7\u7248 Python \u7684\u4f18\u96c5\u5199\u6cd5\uff0cPython 3.5+)\nconfig = {**defaults, **overrides}\n# \u7ed3\u679c: {&#039;host&#039;: &#039;localhost&#039;, &#039;port&#039;: 9000, &#039;timeout&#039;: 30}<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">3. <code>collections.defaultdict<\/code> (\u795e\u5668)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5f53\u9700\u8981\u5904\u7406\u201c\u7f3a\u5931\u952e\u201d\u5e76\u81ea\u52a8\u521d\u59cb\u5316\u9ed8\u8ba4\u503c\u65f6\uff0c<code>defaultdict<\/code> \u6bd4\u666e\u901a\u5b57\u5178\u7684 <code>setdefault<\/code> \u66f4\u9ad8\u6548\u3001\u66f4\u7b80\u6d01\u3002\u5b83\u5728\u8bbf\u95ee\u4e0d\u5b58\u5728\u7684\u952e\u65f6\uff0c\u4f1a\u81ea\u52a8\u8c03\u7528\u4e00\u4e2a\u5de5\u5382\u51fd\u6570\u6765\u751f\u6210\u9ed8\u8ba4\u503c\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from collections import defaultdict\n\n# \u5de5\u5382\u51fd\u6570\u4e3a list\uff0c\u7f3a\u5931\u7684\u952e\u4f1a\u81ea\u52a8\u521d\u59cb\u5316\u4e3a\u7a7a\u5217\u8868 []\ngrouped = defaultdict(list)\nwords = [&quot;apple&quot;, &quot;bat&quot;, &quot;ant&quot;]\nfor word in words:\n    grouped[word[0]].append(word)  # \u65e0\u9700\u68c0\u67e5\u952e\u662f\u5426\u5b58\u5728\uff01\n\nprint(grouped)  # defaultdict(&lt;class &#039;list&#039;&gt;, {&#039;a&#039;: [&#039;apple&#039;, &#039;ant&#039;], &#039;b&#039;: [&#039;bat&#039;]})\n\n# \u5de5\u5382\u51fd\u6570\u4e3a int\uff0c\u7f3a\u5931\u7684\u952e\u81ea\u52a8\u521d\u59cb\u5316\u4e3a 0 (\u5e38\u7528\u4e8e\u8ba1\u6570)\ncounts = defaultdict(int)\nfor char in &quot;hello&quot;:\n    counts[char] += 1\nprint(counts)  # defaultdict(&lt;class &#039;int&#039;&gt;, {&#039;h&#039;: 1, &#039;e&#039;: 1, &#039;l&#039;: 2, &#039;o&#039;: 1})<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">4. <code>collections.Counter<\/code> (\u4e13\u7528\u8ba1\u6570\u5668)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\"><code>Counter<\/code> \u662f <code>dict<\/code> \u7684\u5b50\u7c7b\uff0c\u4e13\u95e8\u7528\u4e8e\u7edf\u8ba1\u53ef\u54c8\u5e0c\u5bf9\u8c61\u7684\u51fa\u73b0\u6b21\u6570\uff0c\u63d0\u4f9b\u4e86\u8bb8\u591a\u4fbf\u6377\u65b9\u6cd5\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">from collections import Counter\n\ntext = &quot;abracadabra&quot;\ncounter = Counter(text)\n\nprint(counter)               # Counter({&#039;a&#039;: 5, &#039;b&#039;: 2, &#039;r&#039;: 2, &#039;c&#039;: 1, &#039;d&#039;: 1})\nprint(counter.most_common(2))# [(&#039;a&#039;, 5), (&#039;b&#039;, 2)] (\u83b7\u53d6\u51fa\u73b0\u6b21\u6570\u6700\u591a\u7684\u524d 2 \u4e2a\u5143\u7d20)\n\n# Counter \u652f\u6301\u6570\u5b66\u8fd0\u7b97\nc1 = Counter(a=3, b=1)\nc2 = Counter(a=1, b=2)\nprint(c1 + c2)  # Counter({&#039;a&#039;: 4, &#039;b&#039;: 3})<\/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 \u5b57\u5178\u7684\u5e95\u5c42\u539f\u7406\u4e0e\u6027\u80fd\u5206\u6790 (\u6df1\u5ea6\u89e3\u6790)<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">\u7406\u89e3\u5b57\u5178\u7684\u5e95\u5c42\u5b9e\u73b0\uff0c\u662f\u5199\u51fa\u9ad8\u6027\u80fd Python \u4ee3\u7801\u7684\u5fc5\u7ecf\u4e4b\u8def\u3002CPython \u4e2d\u7684\u5b57\u5178\u662f\u57fa\u4e8e<strong>\u54c8\u5e0c\u8868 (Hash Table)<\/strong> \u5b9e\u73b0\u7684\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">1. \u54c8\u5e0c\u8868\u7684\u57fa\u672c\u5de5\u4f5c\u539f\u7406<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>\u8ba1\u7b97\u54c8\u5e0c\u503c<\/strong>\uff1a\u5f53\u63d2\u5165\u952e\u503c\u5bf9 <code>key: value<\/code> \u65f6\uff0cPython \u9996\u5148\u8c03\u7528 <code>hash(key)<\/code> \u8ba1\u7b97\u51fa\u4e00\u4e2a\u6574\u6570\u54c8\u5e0c\u503c\u3002<br>to <strong>\u7d22\u5f15\u6620\u5c04<\/strong>\uff1a\u5c06\u8be5\u54c8\u5e0c\u503c\u4e0e\u5b57\u5178\u7684\u5e95\u5c42\u6570\u7ec4\u5927\u5c0f\u8fdb\u884c\u6309\u4f4d\u4e0e\u8fd0\u7b97\uff08\u6216\u53d6\u6a21\uff09\uff0c\u5f97\u5230\u4e00\u4e2a\u6570\u7ec4\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u5b58\u50a8<\/strong>\uff1a\u5728\u8be5\u7d22\u5f15\u4f4d\u7f6e\u5b58\u50a8 <code>(hash, key, value)<\/code> \u7684\u6761\u76ee (Entry)\u3002<\/li>\n\n\n\n<li><strong>\u67e5\u627e<\/strong>\uff1a\u67e5\u627e\u65f6\uff0c\u518d\u6b21\u8ba1\u7b97 <code>hash(key)<\/code>\uff0c\u76f4\u63a5\u8df3\u8f6c\u5230\u5bf9\u5e94\u7684\u7d22\u5f15\u4f4d\u7f6e\u6bd4\u5bf9 <code>key<\/code> \u662f\u5426\u76f8\u7b49\u3002\u5982\u679c\u76f8\u7b49\uff0c\u5219\u8fd4\u56de <code>value<\/code>\u3002<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">\u8fd9\u5c31\u662f\u4e3a\u4ec0\u4e48\u5b57\u5178\u7684\u67e5\u627e\u3001\u63d2\u5165\u548c\u5220\u9664\u64cd\u4f5c\u7684<strong>\u5e73\u5747\u65f6\u95f4\u590d\u6742\u5ea6\u90fd\u662f $O(1)$<\/strong>\uff0c\u8fdc\u5feb\u4e8e\u5217\u8868\u7684 $O(N)$\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u54c8\u5e0c\u51b2\u7a81\u4e0e\u5f00\u653e\u5bfb\u5740\u6cd5 (Open Addressing)<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e0d\u540c\u7684\u952e\u53ef\u80fd\u4f1a\u8ba1\u7b97\u51fa\u76f8\u540c\u7684\u54c8\u5e0c\u503c\uff08\u6216\u6620\u5c04\u5230\u76f8\u540c\u7684\u7d22\u5f15\uff09\uff0c\u8fd9\u79f0\u4e3a<strong>\u54c8\u5e0c\u51b2\u7a81<\/strong>\u3002CPython \u4f7f\u7528<strong>\u5f00\u653e\u5bfb\u5740\u6cd5<\/strong>\u6765\u89e3\u51b3\u51b2\u7a81\uff1a<br>\u5982\u679c\u76ee\u6807\u7d22\u5f15\u5df2\u88ab\u5360\u7528\uff0cPython \u4f1a\u4f7f\u7528\u4e00\u4e2a\u4f2a\u968f\u673a\u63a2\u6d4b\u5e8f\u5217\uff08\u57fa\u4e8e\u54c8\u5e0c\u503c\u7684\u6270\u52a8\uff09\u53bb\u5bfb\u627e\u4e0b\u4e00\u4e2a\u7a7a\u95f2\u7684\u69fd\u4f4d\uff0c\u76f4\u5230\u627e\u5230\u4e3a\u6b62\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">3. Python 3.6+ \u7684\u201c\u7d27\u51d1\u5b57\u5178\u201d\u9769\u547d (\u5185\u5b58\u4f18\u5316) \ud83c\udf1f<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728 Python 3.5 \u53ca\u4e4b\u524d\uff0c\u54c8\u5e0c\u8868\u662f\u4e00\u4e2a\u7a00\u758f\u6570\u7ec4\uff0c\u4e3a\u4e86\u4fdd\u6301\u8f83\u4f4e\u7684\u51b2\u7a81\u7387\uff0c\u6570\u7ec4\u901a\u5e38\u6709 1\/3 \u662f\u7a7a\u7684\uff0c\u8fd9\u5bfc\u81f4\u4e86\u4e25\u91cd\u7684<strong>\u5185\u5b58\u6d6a\u8d39<\/strong>\uff0c\u4e14<strong>\u65e0\u6cd5\u4fdd\u8bc1\u904d\u5386\u987a\u5e8f<\/strong>\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4ece Python 3.6 (CPython \u5b9e\u73b0) \u5f00\u59cb\uff0c\u5e76\u6b63\u5f0f\u7eb3\u5165 Python 3.7 \u89c4\u8303\uff0c\u5b57\u5178\u91c7\u7528\u4e86<strong>\u53cc\u6570\u7ec4\u7ed3\u6784<\/strong>\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Indices Array (\u7d22\u5f15\u6570\u7ec4)<\/strong>\uff1a\u4e00\u4e2a\u7d27\u51d1\u7684\u7a00\u758f\u6570\u7ec4\uff0c\u53ea\u5b58\u50a8\u6574\u6570\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>Entries Array (\u6761\u76ee\u6570\u7ec4)<\/strong>\uff1a\u4e00\u4e2a\u7a20\u5bc6\u6570\u7ec4\uff0c\u6309<strong>\u63d2\u5165\u987a\u5e8f<\/strong>\u4f9d\u6b21\u5b58\u50a8 <code>(hash, key, value)<\/code>\u3002<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u5de5\u4f5c\u6d41\u7a0b<\/strong>\uff1a<br>\u8ba1\u7b97 <code>hash(key)<\/code> -&gt; \u6620\u5c04\u5230 <code>Indices Array<\/code> \u7684\u67d0\u4e2a\u4f4d\u7f6e -&gt; \u8be5\u4f4d\u7f6e\u5b58\u50a8\u7684\u662f <code>Entries Array<\/code> \u4e2d\u7684\u7d22\u5f15 -&gt; \u53bb <code>Entries Array<\/code> \u4e2d\u8bfb\u53d6\u771f\u5b9e\u6570\u636e\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>\u5e26\u6765\u7684\u5de8\u5927\u4f18\u52bf<\/strong>\uff1a<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u8282\u7701\u5185\u5b58<\/strong>\uff1a\u6761\u76ee\u6570\u7ec4\u662f\u7d27\u51d1\u7684\uff0c\u6ca1\u6709\u7a7a\u6d1e\uff0c\u5185\u5b58\u5360\u7528\u51cf\u5c11\u4e86 20% \u5230 25%\u3002<\/li>\n\n\n\n<li><strong>\u4fdd\u6301\u63d2\u5165\u987a\u5e8f<\/strong>\uff1a\u56e0\u4e3a <code>Entries Array<\/code> \u662f\u6309\u63d2\u5165\u987a\u5e8f\u8ffd\u52a0\u7684\uff0c\u904d\u5386\u5b83\u81ea\u7136\u5c31\u4fdd\u6301\u4e86\u987a\u5e8f\u3002<\/li>\n\n\n\n<li><strong>\u8fed\u4ee3\u66f4\u5feb<\/strong>\uff1a\u904d\u5386\u5b57\u5178\u65f6\u53ea\u9700\u7ebf\u6027\u626b\u63cf\u7d27\u51d1\u7684 <code>Entries Array<\/code>\uff0c\u65e0\u9700\u8df3\u8fc7\u7a00\u758f\u7684\u7a7a\u6d1e\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">4. \u5b57\u5178\u64cd\u4f5c\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u603b\u7ed3<\/h4>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th class=\"has-text-align-left\" data-align=\"left\">\u64cd\u4f5c<\/th><th class=\"has-text-align-center\" data-align=\"center\">\u5e73\u5747\u65f6\u95f4\u590d\u6742\u5ea6<\/th><th class=\"has-text-align-center\" data-align=\"center\">\u6700\u574f\u60c5\u51b5\u65f6\u95f4\u590d\u6742\u5ea6<\/th><th class=\"has-text-align-left\" data-align=\"left\">\u8bf4\u660e<\/th><\/tr><\/thead><tbody><tr><td class=\"has-text-align-left\" data-align=\"left\">\u67e5\u627e <code>d[key]<\/code> \/ <code>d.get()<\/code><\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(1)$<\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(N)$<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u6700\u574f\u60c5\u51b5\u53d1\u751f\u5728\u6781\u7aef\u54c8\u5e0c\u51b2\u7a81\u65f6\uff08\u6781\u7f55\u89c1\uff09\u3002<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u63d2\u5165\/\u4fee\u6539 <code>d[key] = value<\/code><\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(1)$<\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(N)$<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u5747\u644a $O(1)$\u3002\u5f53\u54c8\u5e0c\u8868\u6ee1\u8f7d\u65f6\uff0c\u4f1a\u89e6\u53d1<strong>\u6269\u5bb9 (Resize)<\/strong>\uff0c\u9700\u8981\u91cd\u65b0\u8ba1\u7b97\u6240\u6709\u5143\u7d20\u7684\u54c8\u5e0c\u5e76\u8fc1\u79fb\uff0c\u6b64\u65f6\u4e3a $O(N)$\u3002<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u5220\u9664 <code>del d[key]<\/code> \/ <code>pop()<\/code><\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(1)$<\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(N)$<\/td><td class=\"has-text-align-left\" data-align=\"left\">\u5220\u9664\u65f6\u4f1a\u5728\u539f\u4f4d\u7f6e\u63d2\u5165\u4e00\u4e2a\u7279\u6b8a\u7684\u201c\u54d1\u5143 (Dummy)\u201d\u6807\u8bb0\uff0c\u4ee5\u7ef4\u6301\u63a2\u6d4b\u5e8f\u5217\u7684\u5b8c\u6574\u6027\u3002<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u904d\u5386 <code>d.items()<\/code><\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(N)$<\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(N)$<\/td><td class=\"has-text-align-left\" data-align=\"left\">N \u4e3a\u5b57\u5178\u4e2d\u5b9e\u9645\u5b58\u5728\u7684\u5143\u7d20\u4e2a\u6570\uff08\u5f97\u76ca\u4e8e\u7d27\u51d1\u6570\u7ec4\uff0c\u975e\u5e38\u5feb\uff09\u3002<\/td><\/tr><tr><td class=\"has-text-align-left\" data-align=\"left\">\u952e\u5b58\u5728\u6027\u68c0\u67e5 <code>key in d<\/code><\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(1)$<\/td><td class=\"has-text-align-center\" data-align=\"center\">$O(N)$<\/td><td class=\"has-text-align-left\" data-align=\"left\"><strong>\u6781\u5176\u9ad8\u6548<\/strong>\uff0c\u8fd9\u662f\u5b57\u5178\u76f8\u5bf9\u4e8e\u5217\u8868\u7684\u6700\u5927\u4f18\u52bf\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\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. \u952e\u5fc5\u987b\u662f\u201c\u53ef\u54c8\u5e0c\u7684 (Hashable)\u201d<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u53ea\u6709\u4e0d\u53ef\u53d8\u5bf9\u8c61\u624d\u662f\u53ef\u54c8\u5e0c\u7684\u3002\u5c1d\u8bd5\u4f7f\u7528\u5217\u8868\u6216\u5b57\u5178\u4f5c\u4e3a\u952e\u4f1a\u5bfc\u81f4 <code>TypeError: unhashable type<\/code>\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 \u9519\u8bef\nbad_dict = {[1, 2]: &quot;value&quot;}  # TypeError\n\n# \u2705 \u6b63\u786e\uff1a\u4f7f\u7528\u5143\u7ec4\u4f5c\u4e3a\u590d\u5408\u952e\ngood_dict = {(1, 2): &quot;value&quot;} <\/code><\/pre><\/div><\/div>\n\n\n\n<p class=\"wp-block-paragraph\"><em>\u6ce8\u610f<\/em>\uff1a\u81ea\u5b9a\u4e49\u7c7b\u7684\u5b9e\u4f8b\u9ed8\u8ba4\u662f\u53ef\u54c8\u5e0c\u7684\uff08\u57fa\u4e8e\u5176\u5185\u5b58\u5730\u5740 <code>id<\/code>\uff09\u3002\u5982\u679c\u91cd\u5199\u4e86 <code>__eq__<\/code> \u65b9\u6cd5\uff0c\u5fc5\u987b\u540c\u65f6\u91cd\u5199 <code>__hash__<\/code> \u65b9\u6cd5\uff0c\u5426\u5219\u8be5\u5b9e\u4f8b\u5c06\u53d8\u4e3a\u4e0d\u53ef\u54c8\u5e0c\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">2. \u5224\u65ad\u952e\u662f\u5426\u5b58\u5728\u7684\u9ad8\u6548\u65b9\u5f0f<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u68c0\u67e5\u952e\u662f\u5426\u5b58\u5728<\/strong>\uff1a\u59cb\u7ec8\u4f7f\u7528 <code>if key in d:<\/code>\u3002\u8fd9\u662f $O(1)$ \u7684\uff0c\u4e14\u6700\u5177\u53ef\u8bfb\u6027\u3002\u4e0d\u8981\u4f7f\u7528 <code>if key in d.keys():<\/code>\uff0c\u867d\u7136 Python 3 \u4e2d <code>keys()<\/code> \u89c6\u56fe\u7684 <code>in<\/code> \u4e5f\u662f $O(1)$\uff0c\u4f46\u591a\u6b64\u4e00\u4e3e\u3002<\/li>\n\n\n\n<li><strong>\u83b7\u53d6\u503c\u5e76\u5904\u7406\u7f3a\u5931<\/strong>\uff1a\u4f18\u5148\u4f7f\u7528 <code>d.get(key, default)<\/code>\uff0c\u800c\u4e0d\u662f <code>try...except KeyError<\/code>\uff0c\u9664\u975e\u7f3a\u5931\u952e\u662f\u771f\u6b63\u7684\u201c\u5f02\u5e38\u201d\u60c5\u51b5\uff0c\u6216\u8005\u9ed8\u8ba4\u503c\u7684\u8ba1\u7b97\u6210\u672c\u6781\u9ad8\uff08<code>get<\/code> \u4f1a\u59cb\u7ec8\u8ba1\u7b97\u9ed8\u8ba4\u503c\u53c2\u6570\uff0c\u9664\u975e\u4f7f\u7528 <code>defaultdict<\/code> \u6216 <code>setdefault<\/code>\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">3. \u5b57\u5178\u7684\u6d45\u62f7\u8d1d\u4e0e\u6df1\u62f7\u8d1d<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e0e\u5217\u8868\u7c7b\u4f3c\uff0c\u5b57\u5178\u7684 <code>copy()<\/code> \u65b9\u6cd5\u6216 <code>d1 = d2.copy()<\/code> \u53ea\u662f<strong>\u6d45\u62f7\u8d1d<\/strong>\u3002\u5982\u679c\u5b57\u5178\u7684\u503c\u662f\u53ef\u53d8\u5bf9\u8c61\uff08\u5982\u5217\u8868\uff09\uff0c\u4fee\u6539\u526f\u672c\u4e2d\u7684\u5217\u8868\u4f1a\u5f71\u54cd\u539f\u5b57\u5178\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><\/div><pre class=\"chp-pre\" style=\"font-size:14px;\"><code class=\"language-plaintext\">original = {&quot;a&quot;: 1, &quot;b&quot;: [1, 2]}\nshallow = original.copy()\n\nshallow[&quot;b&quot;].append(3)\nprint(original[&quot;b&quot;])  # [1, 2, 3] (\u539f\u5b57\u5178\u88ab\u6c61\u67d3)\n\n# \u2705 \u89e3\u51b3\u65b9\u6848\uff1a\u9700\u8981\u5b8c\u5168\u72ec\u7acb\u65f6\uff0c\u4f7f\u7528 copy.deepcopy\nimport copy\ndeep = copy.deepcopy(original)<\/code><\/pre><\/div><\/div>\n\n\n\n<h4 class=\"wp-block-heading\">4. \u907f\u514d\u5728\u5b57\u5178\u4e2d\u5b58\u50a8\u8fc7\u591a\u76f8\u540c\u54c8\u5e0c\u503c\u7684\u952e<\/h4>\n\n\n\n<p class=\"wp-block-paragraph\">\u867d\u7136 Python \u7684\u54c8\u5e0c\u7b97\u6cd5\uff08\u5982\u5b57\u7b26\u4e32\u7684\u54c8\u5e0c\uff09\u7ecf\u8fc7\u4e86\u7cbe\u5fc3\u8bbe\u8ba1\u4ee5\u62b5\u6297\u51b2\u7a81\uff0c\u4f46\u5982\u679c\u4eba\u4e3a\u6784\u9020\u5927\u91cf\u54c8\u5e0c\u503c\u76f8\u540c\u7684\u952e\uff08\u54c8\u5e0c\u78b0\u649e\u653b\u51fb\uff09\uff0c\u4f1a\u5bfc\u81f4\u5b57\u5178\u64cd\u4f5c\u9000\u5316\u4e3a $O(N)$\u3002\u5728\u5904\u7406\u4e0d\u53d7\u4fe1\u4efb\u7684\u5916\u90e8\u8f93\u5165\u4f5c\u4e3a\u5b57\u5178\u952e\u65f6\uff0c\u9700\u4fdd\u6301\u8b66\u60d5\u3002<\/p>\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 3 \u7684\u5b57\u5178\u4e0d\u4ec5\u662f\u4e00\u4e2a\u7b80\u5355\u7684\u952e\u503c\u5bf9\u5bb9\u5668\uff0c\u5b83\u662f\u7ecf\u8fc7\u6570\u5341\u5e74\u6f14\u8fdb\u7684\u5de5\u7a0b\u6770\u4f5c\u3002<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u8bed\u6cd5\u5c42\u9762<\/strong>\uff1a\u63a8\u5bfc\u5f0f\u3001\u89e3\u5305 <code>**<\/code>\u3001\u4ee5\u53ca Python 3.9 \u7684 <code>|<\/code> \u5408\u5e76\u8fd0\u7b97\u7b26\uff0c\u4f7f\u5176\u64cd\u4f5c\u65e0\u6bd4\u6d41\u7545\u3002<\/li>\n\n\n\n<li><strong>\u529f\u80fd\u5c42\u9762<\/strong>\uff1a<code>defaultdict<\/code> \u548c <code>Counter<\/code> \u7b49\u6269\u5c55\u5de5\u5177\uff0c\u89e3\u51b3\u4e86\u65e0\u6570\u5e38\u89c1\u7684\u6570\u636e\u5904\u7406\u75db\u70b9\u3002<\/li>\n\n\n\n<li><strong>\u5e95\u5c42\u5c42\u9762<\/strong>\uff1a3.6+ \u7684\u7d27\u51d1\u54c8\u5e0c\u8868\u8bbe\u8ba1\uff0c\u5b8c\u7f8e\u517c\u987e\u4e86<strong>\u6781\u81f4\u7684\u5185\u5b58\u6548\u7387<\/strong>\u3001<strong>\u8d85\u5feb\u7684\u67e5\u627e\u901f\u5ea6<\/strong>\u548c<strong>\u53ef\u9884\u6d4b\u7684\u904d\u5386\u987a\u5e8f<\/strong>\u3002<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">\u5728\u65e5\u5e38\u5f00\u53d1\u4e2d\uff0c\u5f53\u4f60\u9700\u8981<strong>\u5feb\u901f\u67e5\u627e<\/strong>\u3001<strong>\u5efa\u7acb\u6620\u5c04\u5173\u7cfb<\/strong>\u6216<strong>\u7edf\u8ba1\u8ba1\u6570<\/strong>\u65f6\uff0c\u5b57\u5178\u6c38\u8fdc\u662f\u7b2c\u4e00\u9009\u62e9\u3002\u719f\u7ec3\u638c\u63e1\u5b57\u5178\u7684\u5404\u79cd\u64cd\u4f5c\u6a21\u5f0f\u548c\u5e95\u5c42\u7279\u6027\uff0c\u662f\u533a\u5206 Python \u65b0\u624b\u4e0e\u8d44\u6df1\u5f00\u53d1\u8005\u7684\u5173\u952e\u6807\u5fd7\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u5982\u679c\u4f60\u5bf9\u5b57\u5178\u5728\u7279\u5b9a\u573a\u666f\u4e0b\u7684\u5e94\u7528\uff08\u5982\uff1a\u5b9e\u73b0 LRU \u7f13\u5b58 <code>functools.lru_cache<\/code>\u3001\u5904\u7406\u5d4c\u5957 JSON \u6570\u636e\u3001\u6216\u81ea\u5b9a\u4e49\u53ef\u54c8\u5e0c\u7c7b\uff09\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\uff0c\u5b57\u5178 (Dictionary, 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