{"id":3406,"date":"2025-05-28T14:57:52","date_gmt":"2025-06-04T07:54:52","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=3406"},"modified":"2025-06-04T14:57:52","modified_gmt":"2025-06-04T07:54:52","slug":"%e4%ba%86%e8%a7%a3python%e4%b8%ad%e7%9a%84class_setitem","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/python\/%e4%ba%86%e8%a7%a3python%e4%b8%ad%e7%9a%84class_setitem\/","title":{"rendered":"\u6df1\u5165\u4e86\u89e3 Python \u4e2d\u7684 `__setitem__()` \u65b9\u6cd5\uff1a\u5c6c\u6027\u8a2d\u5b9a\u7684\u6700\u4f73\u5be6\u8e10"},"content":{"rendered":"

<\/p>\n

\u6df1\u5165\u4e86\u89e3 Python \u4e2d\u7684 `__setitem__()` \u65b9\u6cd5<\/h1>\n

\u5728 Python \u4e2d\uff0c`__setitem__()` \u65b9\u6cd5\u662f\u4e00\u500b\u975e\u5e38\u6709\u7528\u7684\u7279\u6b8a\u65b9\u6cd5\uff0c\u5b83\u5141\u8a31\u4f60\u5728\u985e\u5225\u4e2d\u4ee5\u66f4\u9748\u6d3b\u7684\u65b9\u5f0f\u8a2d\u5b9a\u5c6c\u6027\u3002\u9019\u500b\u65b9\u6cd5\u4f7f\u4f60\u80fd\u5920\u81ea\u5b9a\u7fa9\u5728\u4f7f\u7528\u65b9\u62ec\u865f\u8a2d\u5b9a\u5c6c\u6027\u6642\u7684\u884c\u70ba\uff0c\u4e26\u4e14\u53ef\u4ee5\u52a0\u5f37\u5c0d\u5c6c\u6027\u8a2d\u5b9a\u7684\u63a7\u5236\u3002<\/p>\n

### `__setitem__()` \u65b9\u6cd5\u7684\u57fa\u672c\u7528\u6cd5<\/p>\n

`__setitem__()` \u65b9\u6cd5\u7684\u5b9a\u7fa9\u5982\u4e0b\uff1a<\/p>\n

“`python
\ndef __setitem__(self, key, value):
\n # \u81ea\u5b9a\u7fa9\u5c6c\u6027\u8a2d\u5b9a\u884c\u70ba
\n pass
\n“`<\/p>\n

\u5b83\u63a5\u53d7\u5169\u500b\u53c3\u6578\uff1a`key` \u662f\u5c6c\u6027\u540d\u7a31\uff0c`value` \u662f\u8981\u8a2d\u5b9a\u7684\u503c\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u7bc4\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u4f7f\u7528 `__setitem__()` \u65b9\u6cd5\u4f86\u8a2d\u5b9a\u985e\u5225\u5c6c\u6027\uff1a<\/p>\n

“`python
\nclass MyClass:
\n def __init__(self):
\n self.data = {}<\/p>\n

def __setitem__(self, key, value):
\n self.data[key] = value<\/p>\n

obj = MyClass()
\nobj[‘name’] = ‘John’
\nprint(obj.data) # \u8f38\u51fa: {‘name’: ‘John’}
\n“`<\/p>\n

### \u8a2d\u5b9a\u9810\u8a2d\u503c<\/p>\n

\u4f60\u4e5f\u53ef\u4ee5\u5728 `__setitem__()` \u65b9\u6cd5\u4e2d\u81ea\u5b9a\u7fa9\u5982\u4f55\u8a2d\u5b9a\u9810\u8a2d\u503c\u3002\u4f8b\u5982\uff0c\u7576\u5c6c\u6027\u672a\u88ab\u660e\u78ba\u8a2d\u5b9a\u6642\uff0c\u53ef\u4ee5\u4f7f\u7528\u9810\u8a2d\u503c\uff1a<\/p>\n

“`python
\nclass MyClass:
\n def __init__(self):
\n self.data = {}<\/p>\n

def __setitem__(self, key, value):
\n if key not in self.data:
\n self.data[key] = value<\/p>\n

obj = MyClass()
\nobj[‘age’] = 18
\nobj[‘age’] = 25 # \u4e0d\u6703\u8986\u84cb\u539f\u6709\u7684\u503c
\nprint(obj.data) # \u8f38\u51fa: {‘age’: 18′}
\n“`<\/p>\n

### \u8a2d\u5b9a\u5c6c\u6027\u9650\u5236<\/p>\n

`__setitem__()` \u65b9\u6cd5\u4e5f\u53ef\u4ee5\u7528\u4f86\u9650\u5236\u5c6c\u6027\u7684\u503c\u3002\u4f8b\u5982\uff0c\u5982\u679c\u4f60\u60f3\u8981\u9650\u5236\u67d0\u500b\u5c6c\u6027\u503c\u53ea\u80fd\u5728\u7279\u5b9a\u7bc4\u570d\u5167\uff0c\u4f60\u53ef\u4ee5\u9019\u6a23\u505a\uff1a<\/p>\n

“`python
\nclass MyClass:
\n def __init__(self):
\n self.data = {}<\/p>\n

def __setitem__(self, key, value):
\n if key == ‘age’:
\n if 0 <= value <= 100:\n self.data[key] = value\n else:\n raise ValueError(\"Age must be between 0 and 100.\")\n else:\n self.data[key] = value\n\nobj = MyClass()\nobj['age'] = 25 # \u5408\u6cd5\nobj['age'] = 150 # \u5c07\u5f15\u767c ValueError\n```\n\n\u9019\u6a23\u4e00\u4f86\uff0c\u7576\u4f60\u5728\u985e\u5225\u4e2d\u5efa\u7acb\u7269\u4ef6\u6642\uff0c`age` \u5c6c\u6027\u5c31\u53ea\u80fd\u88ab\u8a2d\u5b9a\u70ba 0 \u5230 100 \u4e4b\u9593\u7684\u503c\uff0c\u9019\u80fd\u6709\u6548\u907f\u514d\u4e0d\u5408\u7406\u7684\u6578\u64da\u8f38\u5165\u3002\n\n### \u5ef6\u4f38\u61c9\u7528\n\n`__setitem__()` \u65b9\u6cd5\u53ef\u4ee5\u7528\u5728\u8a31\u591a\u4e0d\u540c\u7684\u60c5\u6cc1\uff0c\u4f8b\u5982\u8a2d\u8a08\u4e00\u500b\u96c6\u5408\u985e\u5225\uff0c\u6216\u8005\u662f\u81ea\u5b9a\u7fa9\u5b57\u5178\u7684\u884c\u70ba\u3002\u9019\u4f7f\u5f97 Python \u7684\u985e\u5225\u7cfb\u7d71\u975e\u5e38\u9748\u6d3b\uff0c\u80fd\u5920\u6eff\u8db3\u5404\u7a2e\u9700\u6c42\u3002\n\n\u5982\u679c\u4f60\u60f3\u6df1\u5165\u5b78\u7fd2 Python \u985e\u5225\u7684\u4f7f\u7528\uff0c\u53ef\u4ee5\u53c3\u8003\u9019\u7bc7 [Python \u985e\u5225\u8207\u7269\u4ef6\u5c0e\u5411\u7a0b\u5f0f\u8a2d\u8a08\u7684\u6df1\u5165\u6559\u5b78](https:\/\/vocus.cc) \u4f86\u7372\u5f97\u66f4\u591a\u8cc7\u6e90\u548c\u7bc4\u4f8b\u3002\n\n### \u5e38\u898b\u554f\u984c\u89e3\u7b54\uff08Q&A\uff09\n\n**Q1: `__setitem__()` \u65b9\u6cd5\u8207\u666e\u901a\u7684\u5c6c\u6027\u8a2d\u5b9a\u6709\u4ec0\u9ebc\u4e0d\u540c\uff1f** \nA1: `__setitem__()` \u65b9\u6cd5\u5141\u8a31\u4f60\u81ea\u5b9a\u7fa9\u5c6c\u6027\u8a2d\u5b9a\u7684\u884c\u70ba\uff0c\u4e26\u4f7f\u4f60\u80fd\u5920\u63a7\u5236\u5982\u4f55\u8655\u7406\u5c6c\u6027\u503c\uff0c\u9019\u6a23\u53ef\u4ee5\u5be6\u73fe\u66f4\u9748\u6d3b\u7684\u5c6c\u6027\u7ba1\u7406\u3002\n\n**Q2: \u5982\u4f55\u5728 `__setitem__()` \u65b9\u6cd5\u4e2d\u8a2d\u5b9a\u9ed8\u8a8d\u503c\uff1f** \nA2: \u4f60\u53ef\u4ee5\u5728\u65b9\u6cd5\u4e2d\u6aa2\u67e5\u8a72\u5c6c\u6027\u662f\u5426\u5df2\u5b58\u5728\uff0c\u82e5\u4e0d\u5b58\u5728\u5247\u8a2d\u5b9a\u70ba\u9ed8\u8a8d\u503c\uff0c\u5f9e\u800c\u9054\u5230\u81ea\u52d5\u521d\u59cb\u5316\u7684\u76ee\u7684\u3002\n\n**Q3: \u53ef\u4ee5\u5728 `__setitem__()` \u65b9\u6cd5\u4e2d\u4f7f\u7528\u5176\u4ed6\u985e\u5225\u7684\u65b9\u6cd5\u55ce\uff1f** \nA3: \u7576\u7136\u53ef\u4ee5\uff0c\u4f60\u53ef\u4ee5\u5728 `__setitem__()` \u65b9\u6cd5\u5167\u90e8\u8abf\u7528\u5176\u4ed6\u65b9\u6cd5\u4f86\u57f7\u884c\u66f4\u8907\u96dc\u7684\u908f\u8f2f\uff0c\u9019\u4f7f\u5f97\u985e\u5225\u7684\u8a2d\u8a08\u66f4\u52a0\u9748\u6d3b\u3002\n\n---\n\n\u9019\u6a23\u7684\u512a\u5316\u4e0d\u50c5\u66f4\u65b0\u4e86\u8a9e\u6cd5\uff0c\u4e5f\u63d0\u4f9b\u4e86\u66f4\u591a\u5be6\u7528\u7684\u7bc4\u4f8b\u548c\u5ef6\u4f38\u61c9\u7528\uff0c\u4e26\u7b26\u5408 SEO \u6700\u4f73\u5be6\u8e10\u3002\u5e0c\u671b\u9019\u7bc7\u6587\u7ae0\u80fd\u5c0d\u4f60\u6709\u5e6b\u52a9\uff01\n<\/p>\n","protected":false},"excerpt":{"rendered":"

\u4e86\u89e3Python\u4e2d\u7684class_setitem()\uff0c\u5b83\u662f\u4e00\u500b\u53ef\u4ee5\u8a2d\u7f6e\u7269\u4ef6\u5c6c\u6027\u7684\u51fd\u6578\uff0c\u53ef\u4ee5\u8b93\u4f60\u66f4\u5bb9\u6613\u5730\u64cd\u4f5c\u7269\u4ef6\u5c6c\u6027\uff0c\u4e26\u63d0\u4f9b\u66f4\u591a\u7684\u5f48\u6027\u3002\u672c\u6587\u5c07\u8a73\u7d30\u4ecb\u7d39class_setitem()\u7684\u529f\u80fd\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u793a\u4f8b\u4f86\u89e3\u91cb\u5b83\u7684\u4f7f\u7528\u65b9\u6cd5\u3002<\/p>\n","protected":false},"author":1,"featured_media":2518,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[18],"tags":[15],"class_list":["post-3406","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-python","tag-python"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/badgameshow.com\/steven\/wp-content\/uploads\/2022\/12\/DALL\u00b7E-2022-12-28-14.25.55-\u62f7\u8c9d2.png","jetpack-related-posts":[],"jetpack_shortlink":"https:\/\/wp.me\/pcFK27-SW","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3406","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/comments?post=3406"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3406\/revisions"}],"predecessor-version":[{"id":3407,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3406\/revisions\/3407"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media\/2518"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=3406"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=3406"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=3406"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}