{"id":4249,"date":"2025-06-01T11:36:16","date_gmt":"2025-06-05T04:30:15","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=4249"},"modified":"2025-06-05T11:36:16","modified_gmt":"2025-06-05T04:30:15","slug":"%e4%ba%86%e8%a7%a3swift%e4%b8%ad%e8%ae%8a%e6%95%b8x%e7%9a%84let%e5%b8%b8%e6%95%b8%e6%87%89%e7%94%a8-5","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/swift\/%e4%ba%86%e8%a7%a3swift%e4%b8%ad%e8%ae%8a%e6%95%b8x%e7%9a%84let%e5%b8%b8%e6%95%b8%e6%87%89%e7%94%a8-5\/","title":{"rendered":"\u6df1\u5165\u4e86\u89e3 Swift \u4e2d\u7684 `let` \u5e38\u6578\u8207 `var` \u8b8a\u6578\uff1a\u6700\u4f73\u5be6\u8e10\u8207\u932f\u8aa4\u89e3\u6790"},"content":{"rendered":"<p><meta name=\"keywords\" content=\"Swift, Variable, Mutated, Let, Constant, Swift \u6559\u5b78, Swift \u7a0b\u5f0f\u8a2d\u8a08, Swift \u7a0b\u5f0f\u8a9e\u8a00\"><\/p>\n<h1>\u6df1\u5165\u4e86\u89e3 Swift \u4e2d\u7684 `let` \u5e38\u6578\u8207 `var` \u8b8a\u6578\uff1a\u6700\u4f73\u5be6\u8e10\u8207\u932f\u8aa4\u89e3\u6790<\/h1>\n<p>Swift \u662f\u4e00\u7a2e\u529f\u80fd\u5f37\u5927\u7684\u7a0b\u5f0f\u8a9e\u8a00\uff0c\u8a2d\u8a08\u7528\u65bc\u8b93\u958b\u767c\u8005\u66f4\u8f15\u9b06\u5730\u64b0\u5beb\u9ad8\u6548\u3001\u53ef\u8b80\u7684\u7a0b\u5f0f\u78bc\u3002\u5728\u958b\u767c\u904e\u7a0b\u4e2d\uff0c\u958b\u767c\u8005\u53ef\u80fd\u6703\u9047\u5230\u5404\u7a2e\u932f\u8aa4\uff0c\u5176\u4e2d\u4e00\u500b\u5e38\u898b\u7684\u932f\u8aa4\u662f\u300c\u8b8a\u6578 X \u5f9e\u672a\u88ab\u7a81\u8b8a\uff1b\u8003\u616e\u6539\u70ba `let` \u5e38\u6578\u300d\u3002\u9019\u7bc7\u6587\u7ae0\u5c07\u6df1\u5165\u63a2\u8a0e\u8a72\u932f\u8aa4\u7684\u610f\u7fa9\uff0c\u4ee5\u53ca\u5982\u4f55\u6b63\u78ba\u4f7f\u7528 `let` \u548c `var`\u3002<\/p>\n<h2>\u7406\u89e3 `let` \u8207 `var` \u7684\u5dee\u7570<\/h2>\n<p>\u5728 Swift \u4e2d\uff0c`let` \u7528\u65bc\u5ba3\u544a\u5e38\u6578\uff0c\u800c `var` \u7528\u65bc\u5ba3\u544a\u8b8a\u6578\u3002\u9019\u5169\u8005\u7684\u4e3b\u8981\u5dee\u7570\u5728\u65bc\u53ef\u8b8a\u6027\uff1a<\/p>\n<ul>\n<li><strong>let\uff1a<\/strong> \u7528\u65bc\u5ba3\u544a\u4e0d\u53ef\u8b8a\u7684\u5e38\u6578\uff0c\u5ba3\u544a\u5f8c\u5176\u503c\u4e0d\u80fd\u88ab\u66f4\u6539\u3002<\/li>\n<li><strong>var\uff1a<\/strong> \u7528\u65bc\u5ba3\u544a\u53ef\u8b8a\u7684\u8b8a\u6578\uff0c\u5ba3\u544a\u5f8c\u5176\u503c\u53ef\u4ee5\u88ab\u66f4\u6539\u3002<\/li>\n<\/ul>\n<h2>\u7bc4\u4f8b\uff1a\u4f7f\u7528 `let` \u548c `var`<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u8b8a\u6578 `x`\uff0c\u5b83\u7684\u521d\u59cb\u503c\u70ba 10\uff1a<\/p>\n<pre class=\"brush: swift\">\nvar x = 10\n<\/pre>\n<p>\u5982\u679c\u6211\u5011\u9700\u8981\u66f4\u6539 `x` \u7684\u503c\uff0c\u53ef\u4ee5\u9019\u6a23\u505a\uff1a<\/p>\n<pre class=\"brush: swift\">\nx = 20\n<\/pre>\n<p>\u7136\u800c\uff0c\u5982\u679c\u6211\u5011\u5e0c\u671b `x` \u7684\u503c\u4fdd\u6301\u4e0d\u8b8a\uff0c\u6211\u5011\u61c9\u8a72\u4f7f\u7528 `let` \u4f86\u5ba3\u544a\u5b83\uff1a<\/p>\n<pre class=\"brush: swift\">\nlet x = 10\n<\/pre>\n<p>\u9019\u6a23\uff0c`x` \u7684\u503c\u4e0d\u6703\u88ab\u66f4\u6539\uff0c\u5f9e\u800c\u907f\u514d\u51fa\u73fe\u300c\u8b8a\u6578 X \u5f9e\u672a\u88ab\u7a81\u8b8a\uff1b\u8003\u616e\u6539\u70ba `let` \u5e38\u6578\u300d\u7684\u932f\u8aa4\u3002<\/p>\n<h2>\u6700\u4f73\u5be6\u8e10\uff1a\u4f55\u6642\u4f7f\u7528 `let` \u548c `var`<\/h2>\n<p>\u5728\u64b0\u5beb Swift \u7a0b\u5f0f\u78bc\u6642\uff0c\u5efa\u8b70\u9075\u5faa\u4ee5\u4e0b\u6700\u4f73\u5be6\u8e10\uff1a<\/p>\n<ul>\n<li>\u5982\u679c\u8b8a\u6578\u7684\u503c\u5728\u7a0b\u5f0f\u4e2d\u4e0d\u6703\u88ab\u4fee\u6539\uff0c\u8acb\u4f7f\u7528 `let`\u3002<\/li>\n<li>\u5982\u679c\u8b8a\u6578\u7684\u503c\u6703\u5728\u7a0b\u5f0f\u4e2d\u88ab\u4fee\u6539\uff0c\u8acb\u4f7f\u7528 `var`\u3002<\/li>\n<li>\u76e1\u91cf\u5728\u7a0b\u5f0f\u7684\u958b\u59cb\u90e8\u5206\u660e\u78ba\u5ba3\u544a\u8b8a\u6578\uff0c\u4ee5\u63d0\u9ad8\u7a0b\u5f0f\u53ef\u8b80\u6027\u3002<\/li>\n<\/ul>\n<h2>\u5e38\u898b\u932f\u8aa4\u8207\u6392\u9664\u65b9\u6cd5<\/h2>\n<p>\u5728\u4f7f\u7528 `let` \u548c `var` \u6642\uff0c\u958b\u767c\u8005\u53ef\u80fd\u6703\u72af\u4e00\u4e9b\u932f\u8aa4\uff1a<\/p>\n<ul>\n<li>\u932f\u8aa4\u4f7f\u7528 `var` \u4f86\u5ba3\u544a\u4e0d\u9700\u8981\u6539\u8b8a\u7684\u503c\uff0c\u5c0e\u81f4\u4e0d\u5fc5\u8981\u7684\u932f\u8aa4\u63d0\u793a\u3002<\/li>\n<li>\u672a\u6b63\u78ba\u7406\u89e3 `let` \u548c `var` \u7684\u5dee\u7570\uff0c\u5c0e\u81f4\u908f\u8f2f\u932f\u8aa4\u3002<\/li>\n<\/ul>\n<p>\u70ba\u4e86\u907f\u514d\u9019\u4e9b\u932f\u8aa4\uff0c\u958b\u767c\u8005\u61c9\u4ed4\u7d30\u6aa2\u67e5\u8b8a\u6578\u7684\u9700\u6c42\uff0c\u4e26\u6839\u64da\u5be6\u969b\u60c5\u6cc1\u9078\u64c7\u9069\u7576\u7684\u5ba3\u544a\u65b9\u5f0f\u3002<\/p>\n<h2>\u5ef6\u4f38\u61c9\u7528<\/h2>\n<p>\u5728 Swift \u4e2d\uff0c\u9664\u4e86\u57fa\u672c\u7684\u8b8a\u6578\u5ba3\u544a\uff0c\u60a8\u9084\u53ef\u4ee5\u4f7f\u7528\u66f4\u8907\u96dc\u7684\u6578\u64da\u7d50\u69cb\uff0c\u5982\u9663\u5217\u6216\u5b57\u5178\uff0c\u9019\u4e9b\u7d50\u69cb\u4e5f\u53ef\u4ee5\u4f7f\u7528 `let` \u548c `var` \u4f86\u63a7\u5236\u5176\u53ef\u8b8a\u6027\u3002\u4e86\u89e3\u5982\u4f55\u5728\u4e0d\u540c\u7684\u4e0a\u4e0b\u6587\u4e2d\u4f7f\u7528\u9019\u4e9b\u95dc\u9375\u5b57\u5c07\u6709\u52a9\u65bc\u60a8\u64b0\u5beb\u66f4\u9ad8\u6548\u7684\u7a0b\u5f0f\u78bc\u3002<\/p>\n<h2>\u7d50\u8ad6<\/h2>\n<p>\u7e3d\u7d50\u4f86\u8aaa\uff0c\u7576\u958b\u767c\u8005\u5728\u5ba3\u544a\u8b8a\u6578\u6642\uff0c\u61c9\u6839\u64da\u8b8a\u6578\u7684\u7528\u9014\u4f86\u6c7a\u5b9a\u4f7f\u7528 `let` \u9084\u662f `var`\u3002\u5982\u679c\u8b8a\u6578\u7684\u503c\u4e0d\u6703\u88ab\u6539\u8b8a\uff0c\u5247\u61c9\u4f7f\u7528 <span style=\"color: #ff0000; font-weight: bold;\">let<\/span>\uff1b\u5982\u679c\u8b8a\u6578\u7684\u503c\u53ef\u80fd\u6703\u88ab\u6539\u8b8a\uff0c\u5247\u61c9\u4f7f\u7528 <span style=\"color: #ff0000; font-weight: bold;\">var<\/span>\u3002<\/p>\n<h2>Q&#038;A\uff08\u5e38\u898b\u554f\u984c\u89e3\u7b54\uff09<\/h2>\n<h3>1. \u70ba\u4ec0\u9ebc\u4f7f\u7528 `let` \u66f4\u597d\uff1f<\/h3>\n<p>\u4f7f\u7528 `let` \u53ef\u4ee5\u8b93\u60a8\u7684\u7a0b\u5f0f\u78bc\u66f4\u52a0\u5b89\u5168\u548c\u7a69\u5b9a\uff0c\u56e0\u70ba\u5b83\u9632\u6b62\u4e86\u4e0d\u5fc5\u8981\u7684\u8b8a\u66f4\uff0c\u9019\u5c0d\u65bc\u7dad\u8b77\u5927\u578b\u5c08\u6848\u975e\u5e38\u91cd\u8981\u3002<\/p>\n<h3>2. `var` \u548c `let` \u7684\u6027\u80fd\u5dee\u7570\u662f\u4ec0\u9ebc\uff1f<\/h3>\n<p>\u5728\u5927\u591a\u6578\u60c5\u6cc1\u4e0b\uff0c`let` \u548c `var` \u7684\u6027\u80fd\u5dee\u7570\u4e0d\u5927\uff0c\u4f46\u4f7f\u7528 `let` \u53ef\u4ee5\u8b93\u7de8\u8b6f\u5668\u9032\u884c\u66f4\u597d\u7684\u512a\u5316\uff0c\u56e0\u70ba\u5b83\u77e5\u9053\u8a72\u503c\u4e0d\u6703\u6539\u8b8a\u3002<\/p>\n<h3>3. \u5982\u4f55\u9078\u64c7\u9069\u7576\u7684\u8b8a\u6578\u985e\u578b\uff1f<\/h3>\n<p>\u5728\u9078\u64c7\u8b8a\u6578\u985e\u578b\u6642\uff0c\u958b\u767c\u8005\u61c9\u8003\u616e\u8a72\u8b8a\u6578\u7684\u7528\u9014\u548c\u9810\u671f\u7684\u4f7f\u7528\u60c5\u6cc1\uff0c\u4e26\u9078\u64c7\u6700\u5408\u9069\u7684\u985e\u578b\u4f86\u63d0\u9ad8\u7a0b\u5f0f\u78bc\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\u3002<\/p>\n<p>&#8212;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6587\u7ae0\u6458\u8981\uff1a\u672c\u6587\u5c07\u4ecb\u7d39Swift\u4e2d\u8b8a\u6578X\u7684let\u5e38\u6578\u61c9\u7528\uff0c\u8b93\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u597d\u5730\u7406\u89e3\u548c\u4f7f\u7528\u8b8a\u6578X\uff0c\u4ee5\u7372\u5f97\u66f4\u597d\u7684\u7a0b\u5f0f\u6548\u7387\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"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":[174,5],"tags":[173,9],"class_list":["post-4249","post","type-post","status-publish","format-standard","hentry","category-ios","category-swift","tag-ios","tag-swift"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_shortlink":"https:\/\/wp.me\/pcFK27-16x","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4249","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=4249"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4249\/revisions"}],"predecessor-version":[{"id":4250,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4249\/revisions\/4250"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=4249"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=4249"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=4249"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}