{"id":4207,"date":"2025-06-01T12:20:55","date_gmt":"2025-06-05T04:22:55","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=4207"},"modified":"2025-06-05T12:20:55","modified_gmt":"2025-06-05T04:22:55","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%a8-4","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%a8-4\/","title":{"rendered":"\u638c\u63e1 Swift \u4e2d\u7684\u5e38\u6578\u8207\u8b8a\u6578\uff1a\u5f9e\u300clet\u300d\u5230\u300cvar\u300d\u7684\u6b63\u78ba\u61c9\u7528"},"content":{"rendered":"<p>&#8220;`html<br \/>\n<meta name=\"keywords\" content=\"Swift, Variable, Constant, Let, Var, Programming, Swift Tutorial, Best Practices\"><\/p>\n<h1>Swift \u932f\u8aa4\u89e3\u6790\uff1a\u8b8a\u6578\u300cX\u300d\u5f9e\u672a\u88ab\u7a81\u8b8a\uff1b\u8003\u616e\u6539\u70ba\u300clet\u300d\u5e38\u6578<\/h1>\n<p>Swift \u662f\u4e00\u7a2e\u5f37\u5927\u7684\u7a0b\u5f0f\u8a9e\u8a00\uff0c\u5b83\u80fd\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u5bb9\u6613\u5730\u64b0\u5beb\u9ad8\u6548\u7684\u7a0b\u5f0f\u78bc\u3002\u7136\u800c\uff0c\u5c0d\u65bc\u521d\u5b78\u8005\u4f86\u8aaa\uff0c\u5e38\u898b\u7684\u932f\u8aa4\u4e4b\u4e00\u662f\u300c\u8b8a\u6578\u300cX\u300d\u5f9e\u672a\u88ab\u7a81\u8b8a\uff1b\u8003\u616e\u6539\u70ba\u300clet\u300d\u5e38\u6578\u300d\u3002\u9019\u7bc7\u6587\u7ae0\u5c07\u5e6b\u52a9\u4f60\u6df1\u5165\u4e86\u89e3 Swift \u4e2d\u7684\u8b8a\u6578\u548c\u5e38\u6578\uff0c\u4e26\u6559\u4f60\u5982\u4f55\u6b63\u78ba\u4f7f\u7528\u5b83\u5011\u3002<\/p>\n<h2>\u8b8a\u6578\u548c\u5e38\u6578\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u5728 Swift \u4e2d\uff0c\u6709\u5169\u7a2e\u4e3b\u8981\u7684\u8cc7\u6599\u5132\u5b58\u65b9\u5f0f\uff1a\u8b8a\u6578\uff08<code>var<\/code>\uff09\u548c\u5e38\u6578\uff08<code>let<\/code>\uff09\u3002<\/p>\n<ul>\n<li><strong>\u8b8a\u6578\uff08<code>var<\/code>\uff09\uff1a<\/strong>\u53ef\u4ee5\u6539\u8b8a\u5176\u503c\u3002<\/li>\n<li><strong>\u5e38\u6578\uff08<code>let<\/code>\uff09\uff1a<\/strong>\u4e00\u65e6\u88ab\u8ce6\u503c\u5f8c\uff0c\u503c\u4e0d\u53ef\u6539\u8b8a\u3002<\/li>\n<\/ul>\n<h2>\u70ba\u4ec0\u9ebc\u8981\u4f7f\u7528\u5e38\u6578<\/h2>\n<p>\u4f7f\u7528\u5e38\u6578\u7684\u4e3b\u8981\u539f\u56e0\u662f\u63d0\u9ad8\u7a0b\u5f0f\u78bc\u7684\u53ef\u8b80\u6027\u548c\u7a69\u5b9a\u6027\u3002\u5982\u679c\u4f60\u78ba\u5b9a\u67d0\u500b\u503c\u4e0d\u6703\u88ab\u6539\u8b8a\uff0c\u4f7f\u7528 <code>let<\/code> \u53ef\u4ee5\u5e6b\u52a9\u5176\u4ed6\u958b\u767c\u8005\uff08\u6216\u672a\u4f86\u7684\u4f60\uff09\u66f4\u5feb\u7406\u89e3\u7a0b\u5f0f\u78bc\u7684\u610f\u5716\uff0c\u4e26\u4e14\u80fd\u5e6b\u52a9\u7de8\u8b6f\u5668\u9032\u884c\u66f4\u597d\u7684\u512a\u5316\u3002<\/p>\n<h2>\u5be6\u4f5c\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u793a\u4f8b\uff0c\u5c55\u793a\u5982\u4f55\u6b63\u78ba\u4f7f\u7528\u8b8a\u6578\u8207\u5e38\u6578\uff1a<\/p>\n<pre class=\"brush: swift\">\n\/\/ \u4f7f\u7528 var \u5ba3\u544a\u4e00\u500b\u8b8a\u6578\uff0c\u56e0\u70ba\u5176\u503c\u6703\u6539\u8b8a\nvar age = 30\nage += 1  \/\/ \u5e74\u9f61\u589e\u52a0\n\n\/\/ \u4f7f\u7528 let \u5ba3\u544a\u4e00\u500b\u5e38\u6578\uff0c\u56e0\u70ba\u5176\u503c\u4e0d\u6703\u6539\u8b8a\nlet name = \"John Doe\"\n\/\/ name = \"Jane Doe\"  \/\/ \u9019\u5c07\u5c0e\u81f4\u932f\u8aa4\uff0c\u56e0\u70ba\u5e38\u6578\u4e0d\u53ef\u4ee5\u88ab\u91cd\u65b0\u8ce6\u503c\n<\/pre>\n<h2>\u932f\u8aa4\u6392\u9664\uff1a\u907f\u514d\u8b8a\u6578\u672a\u88ab\u7a81\u8b8a\u7684\u63d0\u793a<\/h2>\n<p>\u7576\u4f60\u5728\u4f7f\u7528 <code>var<\/code> \u5ba3\u544a\u8b8a\u6578\u6642\uff0c\u5982\u679c\u5f9e\u672a\u5c0d\u5176\u9032\u884c\u8ce6\u503c\u6216\u7a81\u8b8a\uff0cSwift \u7de8\u8b6f\u5668\u6703\u63d0\u793a\u4f60\u8003\u616e\u6539\u7528 <code>let<\/code>\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u60c5\u6cc1\u53ca\u5176\u89e3\u6c7a\u65b9\u6cd5\uff1a<\/p>\n<ul>\n<li>\u5982\u679c\u4f60\u5ba3\u544a\u4e86\u8b8a\u6578\u4f46\u5f9e\u672a\u6539\u8b8a\u5176\u503c\uff0c\u8acb\u5c07\u5176\u6539\u70ba\u5e38\u6578\uff1a<\/li>\n<pre class=\"brush: swift\">\n    var myString = \"Hello World\"  \/\/ \u9019\u88e1\u6c92\u6709\u66f4\u6539\n    \/\/ \u66f4\u6539\u70ba\n    let myString = \"Hello World\"\n    <\/pre>\n<li>\u5982\u679c\u9700\u8981\u5728\u5f8c\u9762\u66f4\u6539\u503c\uff0c\u90a3\u9ebc\u4fdd\u7559\u4f5c\u70ba\u8b8a\u6578\u4e26\u78ba\u4fdd\u6b63\u78ba\u4f7f\u7528\uff1a<\/li>\n<pre class=\"brush: swift\">\n    var myCounter = 0\n    myCounter += 1  \/\/ \u6b63\u78ba\u4f7f\u7528\u8b8a\u6578\n    <\/pre>\n<\/ul>\n<h2>\u5ef6\u4f38\u61c9\u7528\uff1a\u4f7f\u7528\u5e38\u6578\u8207\u8b8a\u6578\u7684\u6700\u4f73\u5be6\u8e10<\/h2>\n<p>\u5728\u64b0\u5beb\u7a0b\u5f0f\u78bc\u6642\uff0c\u9075\u5faa\u4ee5\u4e0b\u6700\u4f73\u5be6\u8e10\u53ef\u4ee5\u5e6b\u52a9\u4f60\u63d0\u5347\u7a0b\u5f0f\u78bc\u7684\u8cea\u91cf\uff1a<\/p>\n<ul>\n<li>\u512a\u5148\u4f7f\u7528 <code>let<\/code>\uff0c\u53ea\u6709\u5728\u9700\u8981\u6539\u8b8a\u7684\u60c5\u6cc1\u4e0b\u624d\u4f7f\u7528 <code>var<\/code>\u3002<\/li>\n<li>\u5728\u5ba3\u544a\u8b8a\u6578\u8207\u5e38\u6578\u6642\uff0c\u4f7f\u7528\u660e\u78ba\u7684\u8b8a\u6578\u540d\u7a31\uff0c\u4ee5\u63d0\u9ad8\u53ef\u8b80\u6027\u3002<\/li>\n<li>\u5b9a\u671f\u6aa2\u67e5\u4f60\u7684\u7a0b\u5f0f\u78bc\uff0c\u78ba\u4fdd\u4e0d\u5fc5\u8981\u7684\u8b8a\u6578\u88ab\u8f49\u70ba\u5e38\u6578\u3002<\/li>\n<\/ul>\n<h2>\u7d50\u8ad6<\/h2>\n<p>\u7576\u4f60\u5728 Swift \u4e2d\u5ba3\u544a\u8b8a\u6578\u6642\uff0c\u61c9\u8a72\u8003\u616e\u8a72\u8b8a\u6578\u662f\u5426\u6703\u88ab\u7a81\u8b8a\u3002\u5982\u679c\u4e0d\u6703\uff0c\u90a3\u9ebc\u4f7f\u7528 <code>let<\/code> \u4f86\u5ba3\u544a\u8a72\u8b8a\u6578\uff0c\u800c\u4e0d\u662f <code>var<\/code>\uff0c\u9019\u6a23\u53ef\u4ee5\u907f\u514d\u51fa\u73fe\u300c\u8b8a\u6578\u300cX\u300d\u5f9e\u672a\u88ab\u7a81\u8b8a\uff1b\u8003\u616e\u6539\u70ba\u300clet\u300d\u5e38\u6578\u300d\u7684\u932f\u8aa4\uff0c\u4e26\u63d0\u5347\u7a0b\u5f0f\u78bc\u7684\u53ef\u7dad\u8b77\u6027\u3002<\/p>\n<h2>Q&#038;A\uff08\u5e38\u898b\u554f\u984c\u89e3\u7b54\uff09<\/h2>\n<h3>1. \u4ec0\u9ebc\u6642\u5019\u61c9\u8a72\u4f7f\u7528 <code>var<\/code> \u800c\u4e0d\u662f <code>let<\/code>\uff1f<\/h3>\n<p>\u7576\u4f60\u9700\u8981\u4fee\u6539\u67d0\u500b\u503c\uff0c\u6216\u5176\u503c\u5728\u7a0b\u5f0f\u904b\u884c\u904e\u7a0b\u4e2d\u6703\u8b8a\u5316\u6642\uff0c\u61c9\u4f7f\u7528 <code>var<\/code>\u3002<\/p>\n<h3>2. \u4f7f\u7528 <code>let<\/code> \u662f\u5426\u6703\u5f71\u97ff\u6027\u80fd\uff1f<\/h3>\n<p>\u4f7f\u7528 <code>let<\/code> \u53ef\u4ee5\u8b93 Swift \u7de8\u8b6f\u5668\u9032\u884c\u66f4\u597d\u7684\u512a\u5316\uff0c\u5f9e\u800c\u63d0\u9ad8\u6027\u80fd\u3002<\/p>\n<h3>3. \u5982\u679c\u6211\u7684\u8b8a\u6578\u5728\u67d0\u500b\u689d\u4ef6\u4e0b\u624d\u6703\u88ab\u6539\u8b8a\uff0c\u6211\u61c9\u8a72\u5982\u4f55\u5ba3\u544a\uff1f<\/h3>\n<p>\u5728\u9019\u7a2e\u60c5\u6cc1\u4e0b\uff0c\u4f7f\u7528 <code>var<\/code> \u662f\u5408\u7406\u7684\uff0c\u56e0\u70ba\u4f60\u9700\u8981\u78ba\u4fdd\u8b8a\u6578\u53ef\u4ee5\u6839\u64da\u4e0d\u540c\u60c5\u6cc1\u9032\u884c\u4fee\u6539\u3002<\/p>\n<p>&#8220;`<br \/>\n&#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-4207","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\/pcFK27-15R","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4207","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=4207"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4207\/revisions"}],"predecessor-version":[{"id":4208,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4207\/revisions\/4208"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=4207"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=4207"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=4207"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}