{"id":2905,"date":"2023-09-04T22:49:44","date_gmt":"2023-09-04T14:49:44","guid":{"rendered":"https:\/\/jimmyswebnote.com\/?p=2905"},"modified":"2023-09-04T22:50:34","modified_gmt":"2023-09-04T14:50:34","slug":"python-dict","status":"publish","type":"post","link":"https:\/\/jimmyswebnote.com\/python-dict\/","title":{"rendered":"Python \u6559\u5b78 9 &#8211; Python Mapping Type: dict"},"content":{"rendered":"\n<p>dict \u662f Python \u4e2d\u7684 <a href=\"https:\/\/docs.python.org\/3\/library\/stdtypes.html#mapping-types-dict\" target=\"_blank\" rel=\"noreferrer noopener\">mapping type<\/a>\uff0c\u985e\u4f3c js \u4e2d\u7684 object\uff0c\u6bcf\u4e00\u500b element \u90fd\u7531 key \u548c value \u7d44\u6210\u3002<\/p>\n\n\n\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_66_1 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-66452475b1ba0\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-66452475b1ba0\"  aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#1_%E7%89%B9%E6%80%A7\" title=\"1. \u7279\u6027\">1. \u7279\u6027<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#2_%E5%AE%A3%E5%91%8A_dict\" title=\"2. \u5ba3\u544a dict\">2. \u5ba3\u544a dict<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#21_comma-separated_list_of_key_value_pairs_within_braces\" title=\"2.1 comma-separated list of\u00a0key:\u00a0value\u00a0pairs within braces\">2.1 comma-separated list of\u00a0key:\u00a0value\u00a0pairs within braces<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#22_Dict_Comprehension\" title=\"2.2 Dict Comprehension\">2.2 Dict Comprehension<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#23_type_constructor_dict\" title=\"2.3 type constructor: dict()\">2.3 type constructor: dict()<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#3_Common_Operation\" title=\"3. Common Operation\">3. Common Operation<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#31_in\" title=\"3.1 in\">3.1 in<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#32_not_in\" title=\"3.2 not in\">3.2 not in<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#33_dictkey\" title=\"3.3 dict[key]\">3.3 dict[key]<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#34_getkey_default\" title=\"3.4 get(key[, default])\">3.4 get(key[, default])<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#35_lendict\" title=\"3.5 len(dict)\">3.5 len(dict)<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-12\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#4_Iteration_of_Keys_and_Values\" title=\"4. Iteration of Keys and Values\">4. Iteration of Keys and Values<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-13\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#41_listdict\" title=\"4.1 list(dict)\">4.1 list(dict)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-14\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#42_iterdict\" title=\"4.2 iter(dict)\">4.2 iter(dict)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-15\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#43_dictkeys\" title=\"4.3 dict.keys()\">4.3 dict.keys()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-16\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#44_dictvalues\" title=\"4.4 dict.values()\">4.4 dict.values()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-17\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#45_dictitems\" title=\"4.5 dict.items()\">4.5 dict.items()<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-18\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#5_%E6%93%8D%E4%BD%9C_dict\" title=\"5. \u64cd\u4f5c dict\">5. \u64cd\u4f5c dict<\/a><ul class='ez-toc-list-level-3' ><li class='ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-19\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#51_dictkey_value\" title=\"5.1 dict[key] = value\">5.1 dict[key] = value<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-20\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#52_dictsetdefaultkey_default\" title=\"5.2 dict.setdefault(key[,\u00a0default])\">5.2 dict.setdefault(key[,\u00a0default])<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-21\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#53_dictpopkey_default\" title=\"5.3 dict.pop(key[,\u00a0default])\">5.3 dict.pop(key[,\u00a0default])<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-22\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#54_dictpopitem\" title=\"5.4 dict.popitem()\">5.4 dict.popitem()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-23\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#55_del_dictkey\" title=\"5.5 del dict[key]\">5.5 del dict[key]<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-24\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#56_dictcopy\" title=\"5.6 dict.copy()\">5.6 dict.copy()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-25\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#57_dictclear\" title=\"5.7 dict.clear()\">5.7 dict.clear()<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-26\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#58_reverseddict\" title=\"5.8 reversed(dict)\">5.8 reversed(dict)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-27\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#59_dictupdateother\" title=\"5.9 dict.update([other])\">5.9 dict.update([other])<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-28\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#510_dict_other_39\" title=\"5.10 dict | other (3.9+)\">5.10 dict | other (3.9+)<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-29\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#511_dict_other_39\" title=\"5.11 dict |= other (3.9+)\">5.11 dict |= other (3.9+)<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-30\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/#%E5%8F%83%E8%80%83%E8%B3%87%E6%96%99\" title=\"\u53c3\u8003\u8cc7\u6599\">\u53c3\u8003\u8cc7\u6599<\/a><\/li><\/ul><\/nav><\/div>\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"1_%E7%89%B9%E6%80%A7\"><\/span>1. \u7279\u6027<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<ul><li>\u6bcf\u4e00\u500b item \u90fd\u7531 key \u548c value \u7d44\u6210<\/li><li>object \u5167\u4e0d\u6703\u6709\u91cd\u8907\u7684 key<\/li><li>\u5982\u679c\u65b0\u589e\u7684 key-value \u5df2\u7d93\u6709\u76f8\u540c\u7684 key \u5728 dict \u5167\u7684\u8a71\uff0c\u65b0\u7684 value \u6703\u84cb\u6389\u820a\u7684<\/li><\/ul>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"2_%E5%AE%A3%E5%91%8A_dict\"><\/span>2. \u5ba3\u544a dict<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"21_comma-separated_list_of_key_value_pairs_within_braces\"><\/span>2.1 comma-separated list of\u00a0key:\u00a0value\u00a0pairs within braces<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u53ef\u4ee5\u7528\u5927\u62ec\u865f\u5ba3\u544a\uff0c\u6bcf\u500b key-value pair \u7528 &#8216;:&#8217; \u4f86\u5340\u9694<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\n\nprint(type(my_dict))\n&lt;class 'dict'&gt;\nprint(my_dict)\n{'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"22_Dict_Comprehension\"><\/span>2.2 Dict Comprehension<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>Comprehension \u662f Python \u4e2d\u7279\u6b8a\u7684\u8868\u793a\u6cd5\uff0c\u8a73\u7d30\u4ecb\u7d39\u53ef\u4ee5\u53c3\u8003\uff1a<a href=\"https:\/\/jimmyswebnote.com\/python-comprehension-expression\/\" target=\"_blank\" rel=\"noreferrer noopener\">Python Comprehension \u8a9e\u6cd5 \u2013 List Comprehension, Set Comprehension, Dict Comprehension<\/a>\u3002<\/p>\n\n\n\n<p>Dict Comprehension \u7684\u8a9e\u6cd5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">{key: value for item in iterable (if condition)}<\/pre>\n\n\n\n<p>\u81f3\u65bc iterable \u7684\u5b9a\u7fa9\uff0c\u53ef\u4ee5\u53c3\u8003\u9019\u7bc7\uff1a<a href=\"https:\/\/jimmyswebnote.com\/python-iterable-objects\/\" target=\"_blank\" rel=\"noreferrer noopener\">Python Iterable Objects \u4ecb\u7d39<\/a><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {x: x ** 2 for x in range(5)}\nprint(my_dict)\n{0: 0, 1: 1, 2: 4, 3: 9, 4: 16}\n\nmy_dict = {x: x ** 2 for x in range(5) if x % 2 == 1}\nprint(my_dict)\n{1: 1, 3: 9}\n\nmy_dict = {x + 3: x ** 2 for x in range(3)}\nprint(my_dict)\n{3: 0, 4: 1, 5: 4}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"23_type_constructor_dict\"><\/span>2.3 type constructor: dict()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u53ef\u4ee5\u7528 dict \u7684 type constructor \u4f86\u5ba3\u544a dict object\u3002<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\"><em>class&nbsp;<\/em><strong>dict<\/strong>(<em>**kwargs<\/em>)\n<em>class&nbsp;<\/em><strong>dict<\/strong>(<em>mapping<\/em>,&nbsp;<em>**kwargs<\/em>)\n<em>class&nbsp;<\/em><strong>dict<\/strong>(<em>iterable<\/em>,&nbsp;<em>**kwargs<\/em>)<\/pre>\n\n\n\n<p>\u4f7f\u7528 dict \u7684 type constructor \u5efa\u7acb dict object \u7684\u6642\u5019\u6709\u5e7e\u500b\u898f\u5247\uff1a<\/p>\n\n\n\n<ul><li>\u5982\u679c\u6c92\u6709 positional argument\uff0c\u6703\u5efa\u7acb\u7a7a\u7684 dict<\/li><li>\u5982\u679c\u6709 positional argument\uff0c\u4e14\u8a72 argument \u662f\u500b mapping object\uff0c\u90a3\u6703\u5efa\u7acb\u4e00\u500b\u65b0\u7684\u4e00\u6a21\u4e00\u6a23\u7684 mapping object<\/li><li>\u5982\u679c\u6709 positional argument\uff0c\u4e14\u8a72 argument \u4e0d\u662f mapping object\uff0c\u90a3\u9019\u500b argument \u4e00\u5b9a\u8981\u662f iterable object\uff0c\u4e14\u9019\u500b object \u7684\u6bcf\u500b item \u8981\u525b\u597d\u6709\u5169\u500b object\uff0c\u7b2c\u4e00\u500b\u4f5c\u70ba key\uff0c\u7b2c\u4e8c\u500b\u4f5c\u70ba value<\/li><li>\u5982\u679c\u6709 keyword argument\uff0c\u90a3 keyword argument \u5c07\u4f5c\u70ba key-value pair \u65b0\u589e\u7531 positional argument \u5efa\u7acb\u7684 dict object<\/li><\/ul>\n\n\n\n<pre class=\"wp-block-verse\">\u5ef6\u4f38\u95b1\u8b80\uff1a\n<a href=\"https:\/\/jimmyswebnote.com\/python-iterable-objects\" target=\"_blank\" rel=\"noreferrer noopener\">Python Iterable Objects \u4ecb\u7d39<\/a>\n<a href=\"https:\/\/jimmyswebnote.com\/python-function\/#13_function_%E4%B8%AD%E7%9A%84_arguments\" target=\"_blank\" rel=\"noreferrer noopener\">Python \u4e2d\u7684 function arguments<\/a><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\"># \u6c92\u6709 positional argument\nmy_dict = dict()\nprint(my_dict)\n\n# \u6709 positional argument\uff0c\u4e14\u8a72 argument \u662f\u500b mapping object\nmy_dict = dict({'name': 'Jimmy', 'age': 20, 'city': 'Taipei'})\nprint(my_dict)\n\n# \u6709 positional argument\uff0c\u4e14\u8a72 argument \u4e0d\u662f mapping object\uff0c\u90a3\u9019\u500b argument \u4e00\u5b9a\u8981\u662f iterable object\nmy_info = [('name', 'Jimmy'), ('city', 'Taipei')]\nprint(dict(my_info))\n{'name': 'Jimmy', 'city': 'Taipei'}\n\nmy_set = [{'name', 'Jimmy'}, {'city', 'Taipei'}]\nprint(dict(my_set))\n{'Jimmy': 'name', 'city': 'Taipei'}\n\nmy_data = ({'name', 'Jimmy'}, {'city', 'Taipei'})\nprint(dict(my_data))\n{'Jimmy': 'name', 'city': 'Taipei'}\n\n# \u6709 keyword argument\nmy_dict = dict(name='Jimmy', age=20, city='Taipei')\nprint(my_dict)\n{'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\n\nmy_dict = dict({'name': 'Jimmy', 'age': 20}, city='Taipei')\nprint(my_dict)\n{'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"3_Common_Operation\"><\/span>3. Common Operation<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"31_in\"><\/span>3.1 in<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7528\u4f86\u5224\u65b7 dict \u88e1\u9762\u662f\u5426\u5b58\u5728\u67d0\u500b key\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">\nmy_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint('name' in my_dict)\nTrue\nprint('college' in my_dict)\nFalse<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"32_not_in\"><\/span>3.2 not in<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7528\u4f86\u5224\u65b7 dict \u88e1\u9762\u662f\u5426\u4e0d\u5b58\u5728\u67d0\u500b key\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint('name' not in my_dict)\nFalse\nprint('college' not in my_dict)\nTrue<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"33_dictkey\"><\/span>3.3 dict[key]<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u53ef\u4ee5\u7528 key \u4f86\u5b58\u53d6\u5c0d\u61c9\u7684 value\uff0c\u4f46\u5982\u679c\u8a72 key \u4e0d\u5b58\u5728\uff0c\u6703 raise KeyError\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(my_dict['name'])\n'Jimmy'\nprint(my_dict['college'])\nKeyError: 'college'<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"34_getkey_default\"><\/span>3.4 get(key[, default])<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7528 key \u4f86\u5b58\u53d6 value\uff0c\u7b2c\u4e8c\u500b argument \u7528\u4f86\u8868\u793a\u8a72 key \u4e0d\u5b58\u5728\u6642\uff0c\u8981\u56de\u50b3\u4ec0\u9ebc\uff0cdefault value \u662f None\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(my_dict.get('name'))\nJimmy\nprint(my_dict.get('college'))\nNone\nprint(my_dict.get('college', 'key college not exists'))\nkey college not exists<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"35_lendict\"><\/span>3.5 len(dict)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u7528\u4f86\u8868\u793a\u9019\u500b dict \u6709\u5e7e\u5c0d key-value pairs\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(len(my_dict))\n3<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"4_Iteration_of_Keys_and_Values\"><\/span>4. Iteration of Keys and Values<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"41_listdict\"><\/span>4.1 list(dict)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5c07\u9019\u500b dict \u7684\u6240\u6709 keys \u653e\u5230 list \u5f8c\u56de\u50b3\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(list(my_dict))\n['name', 'age', 'city']<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"42_iterdict\"><\/span>4.2 iter(dict)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6703\u5c07 dict \u7684 keys \u4f5c\u70ba iterator \u56de\u50b3\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-verse\">\u5ef6\u4f38\u95b1\u8b80\uff1a<a href=\"https:\/\/jimmyswebnote.com\/python-iterator\/\" target=\"_blank\" rel=\"noreferrer noopener\">Python Iterator \u4ecb\u7d39<\/a><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict_iter = iter(my_dict)\nprint(my_dict_iter)\n&lt;dict_keyiterator object at 0x102526700&gt;\nprint(next(my_dict_iter))\nname\nprint(next(my_dict_iter))\nage\nprint(next(my_dict_iter))\ncity\nprint(next(my_dict_iter))\nStopIteration<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"43_dictkeys\"><\/span>4.3 dict.keys()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6703\u56de\u50b3 <a href=\"https:\/\/docs.python.org\/3\/library\/stdtypes.html#dictionary-view-objects\" target=\"_blank\" rel=\"noreferrer noopener\">dictionary view objects<\/a>\uff0c\u7576 dict \u7684 key \u6709\u8b8a\u52d5\u6642\uff0c\u9019\u500b object \u4e5f\u6703\u4e00\u8d77\u8b8a\u52d5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict_keys = my_dict.keys()\nprint(my_dict_keys)\ndict_keys(['name', 'age', 'city'])\nmy_dict['college'] = 'NTHU'\nprint(my_dict_keys)\ndict_keys(['name', 'age', 'city', 'college'])<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"44_dictvalues\"><\/span>4.4 dict.values()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6703\u56de\u50b3 <a href=\"https:\/\/docs.python.org\/3\/library\/stdtypes.html#dictionary-view-objects\" target=\"_blank\" rel=\"noreferrer noopener\">dictionary view objects<\/a>\uff0c\u7576 dict \u7684 value \u6709\u8b8a\u52d5\u6642\uff0c\u9019\u500b object \u4e5f\u6703\u4e00\u8d77\u8b8a\u52d5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict_values = my_dict.values()\nprint(my_dict_values)\ndict_values(['Jimmy', 20, 'Taipei'])\nmy_dict['college'] = 'NTHU'\nprint(my_dict_values)\ndict_values(['Jimmy', 20, 'Taipei', 'NTHU'])<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"45_dictitems\"><\/span>4.5 dict.items()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6703\u56de\u50b3 <a href=\"https:\/\/docs.python.org\/3\/library\/stdtypes.html#dictionary-view-objects\" target=\"_blank\" rel=\"noreferrer noopener\">dictionary view objects<\/a>\uff0c\u7576 dict \u7684 key, value \u6709\u8b8a\u52d5\u6642\uff0c\u9019\u500b object \u4e5f\u6703\u4e00\u8d77\u8b8a\u52d5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict_items = my_dict.items()\nprint(my_dict_items)\ndict_items([('name', 'Jimmy'), ('age', 20), ('city', 'Taipei')])\nmy_dict['college'] = 'NTHU'\nprint(my_dict_items)\ndict_items([('name', 'Jimmy'), ('age', 20), ('city', 'Taipei'), ('college', 'NTHU')])<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"5_%E6%93%8D%E4%BD%9C_dict\"><\/span>5. \u64cd\u4f5c dict<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"51_dictkey_value\"><\/span>5.1 dict[key] = value<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u66f4\u65b0\u67d0\u500b key \u7684 value\uff0c\u6216\u662f\u65b0\u589e\u67d0\u500b key-value pair\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict['name'] = 'Eric'\nprint(my_dict['name'])\nEric\nmy_dict['college'] = 'NTHU'\nprint(my_dict)\n{'name': 'Eric', 'age': 20, 'city': 'Taipei', 'college': 'NTHU'}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"52_dictsetdefaultkey_default\"><\/span>5.2 dict.setdefault(<em>key<\/em>[,\u00a0<em>default<\/em>])<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5982\u679c key \u5b58\u5728\uff0c\u56de\u50b3\u5c0d\u61c9\u7684 value\uff0c\u5426\u5247\u65b0\u589e key-value pair\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(my_dict.setdefault('name'))\nJimmy\nprint(my_dict.setdefault('college', 'NTHU'))\nNTHU\nprint(my_dict)\n{'name': 'Jimmy', 'age': 20, 'city': 'Taipei', 'college': 'NTHU'}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"53_dictpopkey_default\"><\/span>5.3 dict.pop(<em>key<\/em>[,\u00a0<em>default<\/em>])<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5982\u679c key \u5b58\u5728\uff0c\u5247\u79fb\u9664\u5c0d\u61c9\u7684 key-value pair\uff0c\u4e26\u4e14\u56de\u50b3\u8a72 value\u3002<\/p>\n\n\n\n<p>\u5982\u679c key \u4e0d\u5b58\u5728\uff0c\u9664\u975e\u7d66 default argument\uff0c\u5426\u5247\u6703 raise KeyError\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(my_dict.pop('age'))\n20\nprint(my_dict)\n{'name': 'Jimmy', 'city': 'Taipei'}\nprint(my_dict.pop('college'))\nKeyError: 'college'\nprint(my_dict.pop('college', 'key college not exist'))\nkey college not exist<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"54_dictpopitem\"><\/span>5.4 dict.popitem()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u79fb\u9664 dict \u7684\u6700\u5f8c\u4e00\u500b key-value pair\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(my_dict.popitem())\n('city', 'Taipei')\nprint(my_dict)\n{'name': 'Jimmy', 'age': 20}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"55_del_dictkey\"><\/span>5.5 del dict[key]<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u79fb\u9664\u67d0\u500b key-value pair\uff0c\u5982\u679c\u8a72 key \u4e0d\u5b58\u5728\uff0c\u6703 raise KeyError\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\ndel my_dict['age']\nprint(my_dict)\n{'name': 'Jimmy', 'city': 'Taipei'}\ndel my_dict['college']\nKeyError: 'college'<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"56_dictcopy\"><\/span>5.6 dict.copy()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>shallow copy dict\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_copy_dict = my_dict.copy()\nprint(my_copy_dict)<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"57_dictclear\"><\/span>5.7 dict.clear()<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u6e05\u7a7a dict\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict.clear()\nprint(my_dict)\n{}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"58_reverseddict\"><\/span>5.8 reversed(dict)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u56de\u50b3 reversed key iterator\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nreversed_dict_iterator = reversed(my_dict)\nprint(reversed_dict_iterator)\n&lt;dict_reversekeyiterator object at 0x1026d5940>\nprint(next(reversed_dict_iterator))\ncity\nprint(next(reversed_dict_iterator))\nage\nprint(next(reversed_dict_iterator))\nname\nprint(next(reversed_dict_iterator))\nStopIteration<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"59_dictupdateother\"><\/span>5.9 dict.update([other])<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u66f4\u65b0 dict\uff0cargument \u53ef\u4ee5\u662f dict\uff0c\u4e5f\u53ef\u4ee5\u653e keyword argument\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict.update({'name': 'Eric'})\nprint(my_dict)\n{'name': 'Eric', 'age': 20, 'city': 'Taipei'}\nmy_dict.update(college='NTHU')\nprint(my_dict)\n{'name': 'Eric', 'age': 20, 'city': 'Taipei', 'college': 'NTHU'}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"510_dict_other_39\"><\/span>5.10 dict | other (3.9+)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u5408\u4f75\u5169\u500b dict\uff0c\u5982\u679c\u6709\u4e00\u6a23\u7684 key\uff0c\u5f8c\u9762\u7684 value \u6703\u8986\u84cb\u6389\u524d\u9762\u7684\uff0c\u4e0d\u6703\u6539\u8b8a\u539f\u4f86\u7684 dict\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nprint(my_dict | {'name': 'Eric', 'college': 'NTHU'})\n{'name': 'Eric', 'age': 20, 'city': 'Taipei', 'college': 'NTHU'}\nprint(my_dict)\n{'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"511_dict_other_39\"><\/span>5.11 dict |= other (3.9+)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p>\u548c | operator \u4e00\u6a23\uff0c\u4f46\u6703\u6539\u8b8a\u539f\u4f86\u7684 dict\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code lang=\"python\" class=\"language-python\">my_dict = {'name': 'Jimmy', 'age': 20, 'city': 'Taipei'}\nmy_dict |= {'name': 'Eric', 'college': 'NTHU'}\nprint(my_dict)\n{'name': 'Eric', 'age': 20, 'city': 'Taipei', 'college': 'NTHU'}<\/code><\/pre>\n\n\n\n<h2 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"%E5%8F%83%E8%80%83%E8%B3%87%E6%96%99\"><\/span>\u53c3\u8003\u8cc7\u6599<span class=\"ez-toc-section-end\"><\/span><\/h2>\n\n\n\n<p><a href=\"https:\/\/docs.python.org\/3\/library\/stdtypes.html#mapping-types-dict\" target=\"_blank\" rel=\"noreferrer noopener\">Built-in Types \u2014 Python 3.11.5 documentation<\/a><\/p>\n\n\n\n\n\n<p>\u5982\u679c\u89ba\u5f97\u6211\u7684\u6587\u7ae0\u6709\u5e6b\u52a9\u7684\u8a71\uff0c\u6b61\u8fce\u5e6b\u6211\u7684\u7c89\u5c08\u6309\u8b9a\u54e6~\u8b1d\u8b1d\u4f60\uff01<br><\/p>\n\n<iframe src=\"https:\/\/www.facebook.com\/plugins\/page.php?href=https%3A%2F%2Fwww.facebook.com%2Fjimmyswebnote&amp;tabs=timeline&amp;width=340&amp;height=500&amp;small_header=false&amp;adapt_container_width=true&amp;hide_cover=false&amp;show_facepile=true&amp;appId\" width=\"340\" height=\"500\" style=\"border:none;overflow:hidden\" scrolling=\"no\" frameborder=\"0\" allowfullscreen=\"true\" allow=\"autoplay; clipboard-write; encrypted-media; picture-in-picture; web-share\"><\/iframe>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>dict \u662f Python \u4e2d\u7684 mapping type\uff0c\u985e\u4f3c js \u4e2d\u7684 object\uff0c\u6bcf\u4e00\u500b element &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/jimmyswebnote.com\/python-dict\/\"> <span class=\"screen-reader-text\">Python \u6559\u5b78 9 &#8211; Python Mapping Type: dict<\/span> Read More \u00bb<\/a><\/p>\n","protected":false},"author":1,"featured_media":2911,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[209],"tags":[246,245,247,213],"_links":{"self":[{"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/posts\/2905"}],"collection":[{"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/comments?post=2905"}],"version-history":[{"count":5,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/posts\/2905\/revisions"}],"predecessor-version":[{"id":2913,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/posts\/2905\/revisions\/2913"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/media\/2911"}],"wp:attachment":[{"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/media?parent=2905"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/categories?post=2905"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jimmyswebnote.com\/wp-json\/wp\/v2\/tags?post=2905"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}