{"id":3881,"date":"2025-05-28T13:54:56","date_gmt":"2025-06-04T06:02:56","guid":{"rendered":"https:\/\/badgameshow.com\/steven\/?p=3881"},"modified":"2025-06-04T13:54:56","modified_gmt":"2025-06-04T06:02:56","slug":"%e5%ad%b8%e7%bf%92%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8swift%e4%b8%ad%e7%9a%84%e9%a1%9e%e5%9e%8b%e6%aa%a2%e6%9f%a5%e5%92%8c%e8%bd%89%e6%8f%9b","status":"publish","type":"post","link":"https:\/\/badgameshow.com\/steven\/swift\/%e5%ad%b8%e7%bf%92%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8swift%e4%b8%ad%e7%9a%84%e9%a1%9e%e5%9e%8b%e6%aa%a2%e6%9f%a5%e5%92%8c%e8%bd%89%e6%8f%9b\/","title":{"rendered":"\u6df1\u5165\u63a2\u7d22Swift\u7684\u985e\u578b\u6aa2\u67e5\u8207\u8f49\u63db\u6280\u5de7\uff1a\u4f7f\u7528is\u3001as\u64cd\u4f5c\u7b26\u53ca\u7a7a\u5408\u4f75\u904b\u7b97\u7b26"},"content":{"rendered":"

<\/p>\n

\u6df1\u5165\u63a2\u7d22Swift\u7684\u985e\u578b\u6aa2\u67e5\u8207\u8f49\u63db\u6280\u5de7\uff1a\u4f7f\u7528is\u3001as\u64cd\u4f5c\u7b26\u53ca\u7a7a\u5408\u4f75\u904b\u7b97\u7b26<\/h1>\n

Swift\u662f\u4e00\u7a2e\u529f\u80fd\u5f37\u5927\u7684\u7a0b\u5f0f\u8a9e\u8a00\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bciOS\u548cmacOS\u958b\u767c\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u7279\u6027\u4f86\u63d0\u5347\u958b\u767c\u6548\u7387\uff0c\u5176\u4e2d\u985e\u578b\u6aa2\u67e5\u548c\u8f49\u63db\u662f\u5c24\u70ba\u91cd\u8981\u7684\u529f\u80fd\u3002\u672c\u6587\u5c07\u6df1\u5165\u89e3\u91cb\u5982\u4f55\u5728Swift\u4e2d\u6709\u6548\u5730\u4f7f\u7528is\u548cas\u64cd\u4f5c\u7b26\uff0c\u4ee5\u53ca\u7a7a\u5408\u4f75\u904b\u7b97\u7b26\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u512a\u5316\u7a0b\u5f0f\u78bc\u4e26\u63d0\u9ad8\u7a0b\u5f0f\u7684\u7a69\u5b9a\u6027\u3002<\/p>\n

\u5982\u4f55\u4f7f\u7528is\u548cas\u64cd\u4f5c\u7b26\u9032\u884c\u985e\u578b\u6aa2\u67e5\u8207\u8f49\u63db<\/h2>\n

\u5728Swift\u4e2d\uff0cis\u548cas\u64cd\u4f5c\u7b26\u662f\u9032\u884c\u985e\u578b\u6aa2\u67e5\u548c\u8f49\u63db\u7684\u6838\u5fc3\u5de5\u5177\u3002<\/p>\n

– **is\u64cd\u4f5c\u7b26**\uff1a\u7528\u65bc\u6aa2\u67e5\u4e00\u500b\u8b8a\u91cf\u662f\u5426\u5c6c\u65bc\u67d0\u500b\u7279\u5b9a\u7684\u985e\u578b\u3002\u9019\u5c0d\u65bc\u78ba\u4fdd\u7a0b\u5f0f\u7684\u5b89\u5168\u6027\u81f3\u95dc\u91cd\u8981\u3002\u4f8b\u5982\uff1a<\/p>\n

“`swift
\nlet x: Any = 5
\nif x is Int {
\n print(“x\u662f\u4e00\u500b\u6574\u6578”)
\n}
\n“`<\/p>\n

\u4e0a\u8ff0\u4ee3\u78bc\u6aa2\u67e5\u8b8a\u91cfx\u662f\u5426\u70baInt\u985e\u578b\uff0c\u5982\u679c\u662f\uff0c\u5247\u8f38\u51fa\u201cx\u662f\u4e00\u500b\u6574\u6578\u201d\u3002<\/p>\n

– **as\u64cd\u4f5c\u7b26**\uff1a\u7528\u65bc\u5c07\u4e00\u500b\u8b8a\u91cf\u8f49\u63db\u70ba\u7279\u5b9a\u7684\u985e\u578b\uff0c\u9019\u5728\u9700\u8981\u9032\u884c\u985e\u578b\u5b89\u5168\u7684\u8f49\u63db\u6642\u7279\u5225\u6709\u7528\u3002\u4f8b\u5982\uff1a<\/p>\n

“`swift
\nlet x = 5
\nlet y = Double(x) \/\/ \u76f4\u63a5\u4f7f\u7528Double()\u8f49\u63db
\nprint(y)
\n“`<\/p>\n

\u5728\u9019\u6bb5\u4ee3\u78bc\u4e2d\uff0cx\u88ab\u8f49\u63db\u70baDouble\u985e\u578b\uff0c\u4e26\u5c07\u7d50\u679c\u8ce6\u503c\u7d66y\uff0c\u6700\u5f8c\u8f38\u51fay\u7684\u503c\u3002<\/p>\n

\u4f7f\u7528\u7a7a\u5408\u4f75\u904b\u7b97\u7b26\u9032\u884c\u5b89\u5168\u7684\u985e\u578b\u8f49\u63db<\/h2>\n

\u7a7a\u5408\u4f75\u904b\u7b97\u7b26\uff08??\uff09\u5728Swift\u4e2d\u7528\u65bc\u63d0\u4f9b\u4e00\u7a2e\u5b89\u5168\u7684\u65b9\u5f0f\u4f86\u8655\u7406\u53ef\u9078\u503c\u3002\u5b83\u7684\u57fa\u672c\u7528\u6cd5\u662f\uff1a\u7576\u4e00\u500b\u8b8a\u91cf\u70banil\u6642\uff0c\u8fd4\u56de\u9810\u8a2d\u503c\u3002\u4f8b\u5982\uff1a<\/p>\n

“`swift
\nlet x: Int? = nil
\nlet y = x ?? 0
\nprint(y) \/\/ \u8f38\u51fa0
\n“`<\/p>\n

\u9019\u6bb5\u4ee3\u78bc\u4e2d\u7684x\u70banil\uff0c\u56e0\u6b64y\u88ab\u8ce6\u503c\u70ba0\uff0c\u4fdd\u8b49\u4e86\u7a0b\u5f0f\u7684\u7a69\u5b9a\u6027\u3002<\/p>\n

\u7e3d\u7d50<\/h2>\n

\u5728\u672c\u6587\u4e2d\uff0c\u6211\u5011\u63a2\u8a0e\u4e86Swift\u4e2d\u7684\u985e\u578b\u6aa2\u67e5\u548c\u8f49\u63db\uff0c\u5305\u62ecis\u548cas\u64cd\u4f5c\u7b26\u4ee5\u53ca\u7a7a\u5408\u4f75\u904b\u7b97\u7b26\u3002\u9019\u4e9b\u529f\u80fd\u4e0d\u50c5\u63d0\u5347\u4e86\u7a0b\u5f0f\u78bc\u7684\u53ef\u8b80\u6027\uff0c\u9084\u78ba\u4fdd\u4e86\u7a0b\u5f0f\u7684\u6b63\u78ba\u6027\uff0c\u8b93\u958b\u767c\u8005\u80fd\u5920\u66f4\u52a0\u81ea\u4fe1\u5730\u8655\u7406\u4e0d\u540c\u985e\u578b\u7684\u6578\u64da\u3002\u7121\u8ad6\u60a8\u662fSwift\u521d\u5b78\u8005\u9084\u662f\u7d93\u9a57\u8c50\u5bcc\u7684\u958b\u767c\u8005\uff0c\u638c\u63e1\u9019\u4e9b\u6280\u5de7\u90fd\u5c07\u6709\u52a9\u65bc\u63d0\u5347\u60a8\u7684\u958b\u767c\u6548\u7387\u8207\u7a0b\u5f0f\u78bc\u8cea\u91cf\u3002
\n—<\/p>\n","protected":false},"excerpt":{"rendered":"

\u6587\u7ae0\u6458\u8981\uff1a\u672c\u6587\u5c07\u4ecb\u7d39Swift\u4e2d\u7684\u985e\u578b\u6aa2\u67e5\u548c\u8f49\u63db\uff0c\u5305\u62ec\u4f7f\u7528is\u548cas\u64cd\u4f5c\u7b26\u3001\u4f7f\u7528\u70ba\u7a7a\u5408\u5e76\u904b\u7b97\u7b26\u7b49\uff0c\u8b93\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u6709\u6548\u5730\u4f7f\u7528Swift\u8a9e\u8a00\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-3881","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\/pcFK27-10B","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3881","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=3881"}],"version-history":[{"count":2,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3881\/revisions"}],"predecessor-version":[{"id":3924,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/posts\/3881\/revisions\/3924"}],"wp:attachment":[{"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/media?parent=3881"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/categories?post=3881"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badgameshow.com\/steven\/wp-json\/wp\/v2\/tags?post=3881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}