{"id":4125,"date":"2025-05-29T11:36:54","date_gmt":"2025-06-05T04:12:53","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=4125"},"modified":"2025-06-05T11:36:54","modified_gmt":"2025-06-05T04:12:53","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%a8-2","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%a8-2\/","title":{"rendered":"\u6df1\u5165\u4e86\u89e3 Swift \u4e2d\u7684\u5e38\u6578\u8207\u8b8a\u6578\uff1a\u70ba\u4f55\u9078\u64c7 let \u800c\u975e var\uff1f"},"content":{"rendered":"<p><meta name=\"keywords\" content=\"Swift, Variable, Mutated, Let, Constant, Swift \u6559\u5b78, Swift \u7bc4\u4f8b\"><\/p>\n<h1>\u6df1\u5165\u4e86\u89e3 Swift \u4e2d\u7684\u5e38\u6578\u8207\u8b8a\u6578\uff1a\u70ba\u4f55\u9078\u64c7 let \u800c\u975e var\uff1f<\/h1>\n<p>Swift \u662f\u4e00\u7a2e\u5f37\u5927\u7684\u7a0b\u5f0f\u8a9e\u8a00\uff0c\u8a2d\u8a08\u4e0a\u65e8\u5728\u8b93\u958b\u767c\u8005\u80fd\u5920\u8f15\u9b06\u64b0\u5beb\u5b89\u5168\u4e14\u9ad8\u6548\u7684\u7a0b\u5f0f\u78bc\u3002\u5728\u4f7f\u7528 Swift \u6642\uff0c\u958b\u767c\u8005\u5e38\u5e38\u6703\u9762\u81e8\u9078\u64c7\u4f7f\u7528\u8b8a\u6578\u6216\u5e38\u6578\u7684\u60c5\u6cc1\u3002\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\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e\u9019\u500b\u932f\u8aa4\u7684\u539f\u56e0\u3001\u6b63\u78ba\u7684\u4f7f\u7528\u65b9\u5f0f\uff0c\u4ee5\u53ca\u6700\u4f73\u5be6\u8e10\u3002<\/p>\n<h2>\u7406\u89e3 var \u8207 let \u7684\u5dee\u7570<\/h2>\n<p>\u5728 Swift \u4e2d\uff0c\u8b8a\u6578\u7531\u5169\u7a2e\u95dc\u9375\u5b57\u5ba3\u544a\uff1a<code>var<\/code> \u548c <code>let<\/code>\u3002\u9019\u5169\u8005\u7684\u4e3b\u8981\u5340\u5225\u5728\u65bc\u53ef\u8b8a\u6027\uff1a<\/p>\n<ul>\n<li><strong>var\uff1a<\/strong>\u7528\u65bc\u5ba3\u544a\u53ef\u4ee5\u6539\u8b8a\u7684\u8b8a\u6578\u3002<\/li>\n<li><strong>let\uff1a<\/strong>\u7528\u65bc\u5ba3\u544a\u4e0d\u53ef\u6539\u8b8a\u7684\u5e38\u6578\u3002<\/li>\n<\/ul>\n<h2>\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4f7f\u7528 <code>var<\/code> \u548c <code>let<\/code> \u7684\u7bc4\u4f8b\uff1a<\/p>\n<h3>\u4f7f\u7528 var \u7684\u7bc4\u4f8b<\/h3>\n<pre class=\"brush: swift\">\nvar x = 10\nx = 20  \/\/ x \u7684\u503c\u53ef\u4ee5\u6539\u8b8a\nprint(x)  \/\/ \u8f38\u51fa\uff1a20\n<\/pre>\n<h3>\u4f7f\u7528 let \u7684\u7bc4\u4f8b<\/h3>\n<pre class=\"brush: swift\">\nlet y = 10\n\/\/ y = 20  \/\/ \u9019\u884c\u7a0b\u5f0f\u78bc\u6703\u5f15\u767c\u932f\u8aa4\uff0c\u56e0\u70ba y \u662f\u5e38\u6578\nprint(y)  \/\/ \u8f38\u51fa\uff1a10\n<\/pre>\n<h2>\u932f\u8aa4\u89e3\u6790\uff1a\u8b8a\u6578\u5f9e\u672a\u88ab\u7a81\u8b8a<\/h2>\n<p>\u7576\u4f60\u5728\u7a0b\u5f0f\u4e2d\u4f7f\u7528 <code>var<\/code> \u5ba3\u544a\u4e00\u500b\u8b8a\u6578\uff0c\u4f46\u537b\u6c92\u6709\u5c0d\u5176\u9032\u884c\u4efb\u4f55\u6539\u8b8a\uff0cSwift \u7de8\u8b6f\u5668\u6703\u986f\u793a\u932f\u8aa4\u63d0\u793a\uff1a\u300c\u8b8a\u6578 X \u5f9e\u672a\u88ab\u7a81\u8b8a\uff1b\u8003\u616e\u6539\u70ba <code>let<\/code> \u5e38\u6578\u300d\u3002\u9019\u662f\u56e0\u70ba\u4f7f\u7528 <code>var<\/code> \u5ba3\u544a\u7684\u8b8a\u6578\u61c9\u8a72\u6709\u6539\u8b8a\u7684\u6f5b\u529b\uff0c\u82e5\u4e0d\u9700\u8981\u6539\u8b8a\uff0c\u5247\u5efa\u8b70\u4f7f\u7528 <code>let<\/code>\u3002<\/p>\n<h2>\u6700\u4f73\u5be6\u8e10<\/h2>\n<p>\u9078\u64c7\u4f7f\u7528 <code>let<\/code> \u6216 <code>var<\/code> \u6642\uff0c\u8acb\u9075\u5faa\u4ee5\u4e0b\u6700\u4f73\u5be6\u8e10\uff1a<\/p>\n<ul>\n<li>\u5982\u679c\u8b8a\u6578\u7684\u503c\u4e0d\u6703\u6539\u8b8a\uff0c\u8acb\u4f7f\u7528 <code>let<\/code>\u3002<\/li>\n<li>\u50c5\u5728\u9700\u8981\u8b8a\u66f4\u503c\u6642\u624d\u4f7f\u7528 <code>var<\/code>\u3002<\/li>\n<li>\u9019\u4e0d\u50c5\u80fd\u63d0\u9ad8\u7a0b\u5f0f\u78bc\u7684\u53ef\u8b80\u6027\uff0c\u4e5f\u80fd\u964d\u4f4e\u6f5b\u5728\u7684\u932f\u8aa4\u3002<\/li>\n<\/ul>\n<h2>\u5ef6\u4f38\u61c9\u7528<\/h2>\n<p>\u5728\u5be6\u969b\u958b\u767c\u4e2d\uff0c\u4f7f\u7528\u5e38\u6578\u548c\u8b8a\u6578\u7684\u9078\u64c7\u6703\u5f71\u97ff\u5230\u7a0b\u5f0f\u7684\u6027\u80fd\u548c\u5b89\u5168\u6027\u3002\u4f8b\u5982\uff0c\u5728\u8655\u7406\u5927\u578b\u6578\u64da\u96c6\u6642\uff0c\u4f7f\u7528\u5e38\u6578\u53ef\u4ee5\u5e6b\u52a9\u7de8\u8b6f\u5668\u9032\u884c\u66f4\u597d\u7684\u512a\u5316\uff0c\u5f9e\u800c\u63d0\u9ad8\u6548\u80fd\u3002<\/p>\n<h2>\u7d50\u8ad6<\/h2>\n<p>\u4e86\u89e3\u4f55\u6642\u4f7f\u7528 <code>let<\/code> \u548c <code>var<\/code> \u662f\u64b0\u5beb Swift \u7a0b\u5f0f\u7684\u57fa\u672c\u6280\u80fd\u3002\u7576\u9700\u8981\u4e0d\u8b8a\u7684\u503c\u6642\uff0c\u9078\u64c7 <code>let<\/code> \u4e0d\u50c5\u6709\u52a9\u65bc\u9632\u6b62\u932f\u8aa4\uff0c\u4e5f\u80fd\u8b93\u7a0b\u5f0f\u78bc\u66f4\u6e05\u6670\u6613\u61c2\u3002<\/p>\n<h2>Q&#038;A\uff08\u5e38\u898b\u554f\u984c\u89e3\u7b54\uff09<\/h2>\n<h3>Q1: \u70ba\u4ec0\u9ebc\u8981\u4f7f\u7528 let \u800c\u4e0d\u662f var\uff1f<\/h3>\n<p>A1: \u4f7f\u7528 <code>let<\/code> \u53ef\u78ba\u4fdd\u8b8a\u6578\u7684\u503c\u4e0d\u6703\u88ab\u6539\u8b8a\uff0c\u9019\u6709\u52a9\u65bc\u63d0\u9ad8\u7a0b\u5f0f\u78bc\u7684\u7a69\u5b9a\u6027\u548c\u53ef\u8b80\u6027\u3002<\/p>\n<h3>Q2: \u5728\u4ec0\u9ebc\u60c5\u6cc1\u4e0b\u61c9\u8a72\u4f7f\u7528 var\uff1f<\/h3>\n<p>A2: \u7576\u9700\u8981\u7d93\u5e38\u6539\u8b8a\u8b8a\u6578\u7684\u503c\u6642\uff0c\u61c9\u4f7f\u7528 <code>var<\/code>\u3002\u4f8b\u5982\uff0c\u8a08\u7b97\u7d2f\u52a0\u7684\u7e3d\u548c\u6642\uff0c\u53ef\u4ee5\u4f7f\u7528 <code>var<\/code>\u3002<\/p>\n<h3>Q3: Swift \u4e2d\u9084\u6709\u5176\u4ed6\u985e\u4f3c\u7684\u932f\u8aa4\u63d0\u793a\u55ce\uff1f<\/h3>\n<p>A3: \u662f\u7684\uff0cSwift \u4e2d\u6709\u8a31\u591a\u932f\u8aa4\u63d0\u793a\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u8b58\u5225\u6f5b\u5728\u7684\u554f\u984c\uff0c\u4e86\u89e3\u9019\u4e9b\u63d0\u793a\u6709\u52a9\u65bc\u63d0\u5347\u7a0b\u5f0f\u78bc\u54c1\u8cea\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\u66f4\u52a0\u4e86\u89e3Swift\u4e2d\u8b8a\u6578X\u7684\u4f7f\u7528\u65b9\u5f0f\uff0c\u4ee5\u53ca\u5982\u4f55\u907f\u514d\u51fa\u73fe\u932f\u8aa4\u89e3\u6790\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-4125","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\/pcFK27-14x","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4125","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=4125"}],"version-history":[{"count":1,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4125\/revisions"}],"predecessor-version":[{"id":4126,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/4125\/revisions\/4126"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=4125"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=4125"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=4125"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}