{"id":538,"date":"2018-02-23T23:39:05","date_gmt":"2018-02-23T15:39:05","guid":{"rendered":"http:\/\/60.205.208.74\/2018\/02\/23\/swift-%e5%b1%9e%e6%80%a7\/"},"modified":"2018-02-23T23:39:05","modified_gmt":"2018-02-23T15:39:05","slug":"swift-%e5%b1%9e%e6%80%a7","status":"publish","type":"post","link":"https:\/\/www.puzi7.net\/?p=538","title":{"rendered":"Swift \u5c5e\u6027"},"content":{"rendered":"
\n
\n

Swift \u5c5e\u6027<\/h1>\n

Swift \u5c5e\u6027\u5c06\u503c\u8ddf\u7279\u5b9a\u7684\u7c7b\u3001\u7ed3\u6784\u6216\u679a\u4e3e\u5173\u8054\u3002<\/p>\n

\u5c5e\u6027\u53ef\u5206\u4e3a\u5b58\u50a8\u5c5e\u6027\u548c\u8ba1\u7b97\u5c5e\u6027:<\/p>\n\n\n\n\n\n
\u5b58\u50a8\u5c5e\u6027<\/b><\/th>\n\u8ba1\u7b97\u5c5e\u6027<\/b><\/th>\n<\/tr>\n
\u5b58\u50a8\u5e38\u91cf\u6216\u53d8\u91cf\u4f5c\u4e3a\u5b9e\u4f8b\u7684\u4e00\u90e8\u5206<\/td>\n\u8ba1\u7b97\uff08\u800c\u4e0d\u662f\u5b58\u50a8\uff09\u4e00\u4e2a\u503c <\/td>\n<\/tr>\n
\u7528\u4e8e\u7c7b\u548c\u7ed3\u6784\u4f53<\/td>\n\u7528\u4e8e\u7c7b\u3001\u7ed3\u6784\u4f53\u548c\u679a\u4e3e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5b58\u50a8\u5c5e\u6027\u548c\u8ba1\u7b97\u5c5e\u6027\u901a\u5e38\u7528\u4e8e\u7279\u5b9a\u7c7b\u578b\u7684\u5b9e\u4f8b\u3002\n<\/p>\n

\u5c5e\u6027\u4e5f\u53ef\u4ee5\u76f4\u63a5\u7528\u4e8e\u7c7b\u578b\u672c\u8eab\uff0c\u8fd9\u79cd\u5c5e\u6027\u79f0\u4e3a\u7c7b\u578b\u5c5e\u6027\u3002\n<\/p>\n

\n\u53e6\u5916\uff0c\u8fd8\u53ef\u4ee5\u5b9a\u4e49\u5c5e\u6027\u89c2\u5bdf\u5668\u6765\u76d1\u63a7\u5c5e\u6027\u503c\u7684\u53d8\u5316\uff0c\u4ee5\u6b64\u6765\u89e6\u53d1\u4e00\u4e2a\u81ea\u5b9a\u4e49\u7684\u64cd\u4f5c\u3002\u5c5e\u6027\u89c2\u5bdf\u5668\u53ef\u4ee5\u6dfb\u52a0\u5230\u81ea\u5df1\u5199\u7684\u5b58\u50a8\u5c5e\u6027\u4e0a\uff0c\u4e5f\u53ef\u4ee5\u6dfb\u52a0\u5230\u4ece\u7236\u7c7b\u7ee7\u627f\u7684\u5c5e\u6027\u4e0a\u3002\n<\/p>\n

\n

\u5b58\u50a8\u5c5e\u6027<\/h2>\n

\n\u7b80\u5355\u6765\u8bf4\uff0c\u4e00\u4e2a\u5b58\u50a8\u5c5e\u6027\u5c31\u662f\u5b58\u50a8\u5728\u7279\u5b9a\u7c7b\u6216\u7ed3\u6784\u4f53\u7684\u5b9e\u4f8b\u91cc\u7684\u4e00\u4e2a\u5e38\u91cf\u6216\u53d8\u91cf\u3002<\/p>\n

\u5b58\u50a8\u5c5e\u6027\u53ef\u4ee5\u662f\u53d8\u91cf\u5b58\u50a8\u5c5e\u6027\uff08\u7528\u5173\u952e\u5b57var\u5b9a\u4e49\uff09\uff0c\u4e5f\u53ef\u4ee5\u662f\u5e38\u91cf\u5b58\u50a8\u5c5e\u6027\uff08\u7528\u5173\u952e\u5b57let\u5b9a\u4e49\uff09\u3002<\/p>\n

    \n
  • \n

    \u53ef\u4ee5\u5728\u5b9a\u4e49\u5b58\u50a8\u5c5e\u6027\u7684\u65f6\u5019\u6307\u5b9a\u9ed8\u8ba4\u503c<\/p>\n<\/li>\n

  • \n

    \u4e5f\u53ef\u4ee5\u5728\u6784\u9020\u8fc7\u7a0b\u4e2d\u8bbe\u7f6e\u6216\u4fee\u6539\u5b58\u50a8\u5c5e\u6027\u7684\u503c\uff0c\u751a\u81f3\u4fee\u6539\u5e38\u91cf\u5b58\u50a8\u5c5e\u6027\u7684\u503c<\/p>\n<\/li>\n<\/ul>\n

    \nimport Cocoa\n\nstruct Number\n{\n   var digits: Int\n   let pi = 3.1415\n}\n\nvar n = Number(digits: 12345)\nn.digits = 67\n\nprint(\"\\(n.digits)\")\nprint(\"\\(n.pi)\")\n<\/pre>\n
    \u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n
    \n67\n3.1415\n<\/pre>\n
    \u8003\u8651\u4ee5\u4e0b\u4ee3\u7801\uff1a<\/p>\n
    let pi = 3.1415<\/pre>\n
    \u4ee3\u7801\u4e2d pi \u5728\u5b9a\u4e49\u5b58\u50a8\u5c5e\u6027\u7684\u65f6\u5019\u6307\u5b9a\u9ed8\u8ba4\u503c\uff08pi = 3.1415\uff09\uff0c\u6240\u4ee5\u4e0d\u7ba1\u4f60\u4ec0\u4e48\u65f6\u5019\u5b9e\u4f8b\u5316\u7ed3\u6784\u4f53\uff0c\u5b83\u90fd\u4e0d\u4f1a\u6539\u53d8\u3002<\/p>\n
    \u5982\u679c\u4f60\u5b9a\u4e49\u7684\u662f\u4e00\u4e2a\u5e38\u91cf\u5b58\u50a8\u5c5e\u6027\uff0c\u5982\u679c\u5c1d\u8bd5\u4fee\u6539\u5b83\u5c31\u4f1a\u62a5\u9519\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
    \nimport Cocoa\n\nstruct Number\n{\n    var digits: Int\n    let numbers = 3.1415\n}\n\nvar n = Number(digits: 12345)\nn.digits = 67\n\nprint(\"\\(n.digits)\")\nprint(\"\\(n.numbers)\")\nn.numbers = 8.7\n<\/pre>\n
    \u4ee5\u4e0a\u7a0b\u5e8f\uff0c\u6267\u884c\u4f1a\u62a5\u9519\uff0c\u9519\u8bef\u5982\u4e0b\u6240\u793a\uff1a<\/p>\n
    \nerror: cannot assign to property: 'numbers' is a 'let' constant\nn.numbers = 8.7\n<\/pre>\n
    \u610f\u601d\u4e3a ‘numbers’ \u662f\u4e00\u4e2a\u5e38\u91cf\uff0c\u4f60\u4e0d\u80fd\u4fee\u6539\u5b83\u3002<\/p>\n
    \n
    \u5ef6\u8fdf\u5b58\u50a8\u5c5e\u6027<\/h2>\n
    \u5ef6\u8fdf\u5b58\u50a8\u5c5e\u6027\u662f\u6307\u5f53\u7b2c\u4e00\u6b21\u88ab\u8c03\u7528\u7684\u65f6\u5019\u624d\u4f1a\u8ba1\u7b97\u5176\u521d\u59cb\u503c\u7684\u5c5e\u6027\u3002<\/p>\n
    \u5728\u5c5e\u6027\u58f0\u660e\u524d\u4f7f\u7528 lazy<\/b> \u6765\u6807\u793a\u4e00\u4e2a\u5ef6\u8fdf\u5b58\u50a8\u5c5e\u6027\u3002<\/p>\n
    \n
    \u6ce8\u610f\uff1a
    \u5fc5\u987b\u5c06\u5ef6\u8fdf\u5b58\u50a8\u5c5e\u6027\u58f0\u660e\u6210\u53d8\u91cf\uff08\u4f7f\u7528var<\/code>\u5173\u952e\u5b57\uff09\uff0c\u56e0\u4e3a\u5c5e\u6027\u7684\u503c\u5728\u5b9e\u4f8b\u6784\u9020\u5b8c\u6210\u4e4b\u524d\u53ef\u80fd\u65e0\u6cd5\u5f97\u5230\u3002\u800c\u5e38\u91cf\u5c5e\u6027\u5728\u6784\u9020\u8fc7\u7a0b\u5b8c\u6210\u4e4b\u524d\u5fc5\u987b\u8981\u6709\u521d\u59cb\u503c\uff0c\u56e0\u6b64\u65e0\u6cd5\u58f0\u660e\u6210\u5ef6\u8fdf\u5c5e\u6027\u3002  <\/p>\n<\/blockquote>\n
    \u5ef6\u8fdf\u5b58\u50a8\u5c5e\u6027\u4e00\u822c\u7528\u4e8e\uff1a<\/p>\n
      \n
    • \n
      \u5ef6\u8fdf\u5bf9\u8c61\u7684\u521b\u5efa\u3002<\/p>\n<\/li>\n
    • \n
      \u5f53\u5c5e\u6027\u7684\u503c\u4f9d\u8d56\u4e8e\u5176\u4ed6\u672a\u77e5\u7c7b<\/p>\n<\/li>\n<\/ul>\n
      \nimport Cocoa\n\nclass sample {\n    lazy var no = number() \/\/ `var` \u5173\u952e\u5b57\u662f\u5fc5\u987b\u7684\n}\n\nclass number {\n    var name = \"Runoob Swift \u6559\u7a0b\"\n}\n\nvar firstsample = sample()\nprint(firstsample.no.name)\n<\/pre>\n
      \u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n
      \nRunoob Swift \u6559\u7a0b\n<\/pre>\n
      \n
      \u5b9e\u4f8b\u5316\u53d8\u91cf<\/h2>\n
      \u5982\u679c\u60a8\u6709\u8fc7 Objective-C \u7ecf\u9a8c\uff0c\u5e94\u8be5\u77e5\u9053Objective-C \u4e3a\u7c7b\u5b9e\u4f8b\u5b58\u50a8\u503c\u548c\u5f15\u7528\u63d0\u4f9b\u4e24\u79cd\u65b9\u6cd5\u3002\u5bf9\u4e8e\u5c5e\u6027\u6765\u8bf4\uff0c\u4e5f\u53ef\u4ee5\u4f7f\u7528\u5b9e\u4f8b\u53d8\u91cf\u4f5c\u4e3a\u5c5e\u6027\u503c\u7684\u540e\u7aef\u5b58\u50a8\u3002<\/p>\n
      Swift \u7f16\u7a0b\u8bed\u8a00\u4e2d\u628a\u8fd9\u4e9b\u7406\u8bba\u7edf\u4e00\u7528\u5c5e\u6027\u6765\u5b9e\u73b0\u3002Swift \u4e2d\u7684\u5c5e\u6027\u6ca1\u6709\u5bf9\u5e94\u7684\u5b9e\u4f8b\u53d8\u91cf\uff0c\u5c5e\u6027\u7684\u540e\u7aef\u5b58\u50a8\u4e5f\u65e0\u6cd5\u76f4\u63a5\u8bbf\u95ee\u3002\u8fd9\u5c31\u907f\u514d\u4e86\u4e0d\u540c\u573a\u666f\u4e0b\u8bbf\u95ee\u65b9\u5f0f\u7684\u56f0\u6270\uff0c\u540c\u65f6\u4e5f\u5c06\u5c5e\u6027\u7684\u5b9a\u4e49\u7b80\u5316\u6210\u4e00\u4e2a\u8bed\u53e5\u3002<\/p>\n
      \n\u4e00\u4e2a\u7c7b\u578b\u4e2d\u5c5e\u6027\u7684\u5168\u90e8\u4fe1\u606f\u2014\u2014\u5305\u62ec\u547d\u540d\u3001\u7c7b\u578b\u548c\u5185\u5b58\u7ba1\u7406\u7279\u5f81\u2014\u2014\u90fd\u5728\u552f\u4e00\u4e00\u4e2a\u5730\u65b9\uff08\u7c7b\u578b\u5b9a\u4e49\u4e2d\uff09\u5b9a\u4e49\u3002<\/p>\n
      \n
      \u8ba1\u7b97\u5c5e\u6027<\/h2>\n
      \u9664\u5b58\u50a8\u5c5e\u6027\u5916\uff0c\u7c7b\u3001\u7ed3\u6784\u4f53\u548c\u679a\u4e3e\u53ef\u4ee5\u5b9a\u4e49\u8ba1\u7b97\u5c5e\u6027<\/em>\uff0c\u8ba1\u7b97\u5c5e\u6027\u4e0d\u76f4\u63a5\u5b58\u50a8\u503c\uff0c\u800c\u662f\u63d0\u4f9b\u4e00\u4e2a getter \u6765\u83b7\u53d6\u503c\uff0c\u4e00\u4e2a\u53ef\u9009\u7684 setter \u6765\u95f4\u63a5\u8bbe\u7f6e\u5176\u4ed6\u5c5e\u6027\u6216\u53d8\u91cf\u7684\u503c\u3002<\/p>\n
      \nimport Cocoa\n\nclass sample {\n    var no1 = 0.0, no2 = 0.0\n    var length = 300.0, breadth = 150.0\n    \n    var middle: (Double, Double) {\n        get{\n            return (length \/ 2, breadth \/ 2)\n        }\n        set(axis){\n            no1 = axis.0 - (length \/ 2)\n            no2 = axis.1 - (breadth \/ 2)\n        }\n    }\n}\n\nvar result = sample()\nprint(result.middle)\nresult.middle = (0.0, 10.0)\n\nprint(result.no1)\nprint(result.no2)\n<\/pre>\n
      \u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n
      \n(150.0, 75.0)\n-150.0\n-65.0\n<\/pre>\n
      \n\u5982\u679c\u8ba1\u7b97\u5c5e\u6027\u7684 setter \u6ca1\u6709\u5b9a\u4e49\u8868\u793a\u65b0\u503c\u7684\u53c2\u6570\u540d\uff0c\u5219\u53ef\u4ee5\u4f7f\u7528\u9ed8\u8ba4\u540d\u79f0 newValue\u3002\n<\/p>\n
      \n
      \u53ea\u8bfb\u8ba1\u7b97\u5c5e\u6027<\/h2>\n
      \u53ea\u6709 getter \u6ca1\u6709 setter \u7684\u8ba1\u7b97\u5c5e\u6027\u5c31\u662f\u53ea\u8bfb\u8ba1\u7b97\u5c5e\u6027\u3002<\/p>\n
      \u53ea\u8bfb\u8ba1\u7b97\u5c5e\u6027\u603b\u662f\u8fd4\u56de\u4e00\u4e2a\u503c\uff0c\u53ef\u4ee5\u901a\u8fc7\u70b9(.)\u8fd0\u7b97\u7b26\u8bbf\u95ee\uff0c\u4f46\u4e0d\u80fd\u8bbe\u7f6e\u65b0\u7684\u503c\u3002<\/p>\n
      \nimport Cocoa\n\nclass film {\n    var head = \"\"\n    var duration = 0.0\n    var metaInfo: [String:String] {\n        return [\n            \"head\": self.head,\n            \"duration\":\"\\(self.duration)\"\n        ]\n    }\n}\n\nvar movie = film()\nmovie.head = \"Swift \u5c5e\u6027\"\nmovie.duration = 3.09\n\nprint(movie.metaInfo[\"head\"]!)\nprint(movie.metaInfo[\"duration\"]!)\n<\/pre>\n
      \u4ee5\u4e0a\u7a0b\u5e8f\u6267\u884c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n
      \nSwift \u5c5e\u6027\n3.09\n<\/pre>\n
      \n
      \u6ce8\u610f\uff1a<\/p>\n
      \u5fc5\u987b\u4f7f\u7528var<\/code>\u5173\u952e\u5b57\u5b9a\u4e49\u8ba1\u7b97\u5c5e\u6027\uff0c\u5305\u62ec\u53ea\u8bfb\u8ba1\u7b97\u5c5e\u6027\uff0c\u56e0\u4e3a\u5b83\u4eec\u7684\u503c\u4e0d\u662f\u56fa\u5b9a\u7684\u3002let<\/code>\u5173\u952e\u5b57\u53ea\u7528\u6765\u58f0\u660e\u5e38\u91cf\u5c5e\u6027\uff0c\u8868\u793a\u521d\u59cb\u5316\u540e\u518d\u4e5f\u65e0\u6cd5\u4fee\u6539\u7684\u503c\u3002<\/p>\n<\/blockquote>\n
      \n
      \u5c5e\u6027\u89c2\u5bdf\u5668<\/h2>\n
      \u5c5e\u6027\u89c2\u5bdf\u5668\u76d1\u63a7\u548c\u54cd\u5e94\u5c5e\u6027\u503c\u7684\u53d8\u5316\uff0c\u6bcf\u6b21\u5c5e\u6027\u88ab\u8bbe\u7f6e\u503c\u7684\u65f6\u5019\u90fd\u4f1a\u8c03\u7528\u5c5e\u6027\u89c2\u5bdf\u5668\uff0c\u751a\u81f3\u65b0\u7684\u503c\u548c\u73b0\u5728\u7684\u503c\u76f8\u540c\u7684\u65f6\u5019\u4e5f\u4e0d\u4f8b\u5916\u3002<\/p>\n
      \u53ef\u4ee5\u4e3a\u9664\u4e86\u5ef6\u8fdf\u5b58\u50a8\u5c5e\u6027\u4e4b\u5916\u7684\u5176\u4ed6\u5b58\u50a8\u5c5e\u6027\u6dfb\u52a0\u5c5e\u6027\u89c2\u5bdf\u5668\uff0c\u4e5f\u53ef\u4ee5\u901a\u8fc7\u91cd\u8f7d\u5c5e\u6027\u7684\u65b9\u5f0f\u4e3a\u7ee7\u627f\u7684\u5c5e\u6027\uff08\u5305\u62ec\u5b58\u50a8\u5c5e\u6027\u548c\u8ba1\u7b97\u5c5e\u6027\uff09\u6dfb\u52a0\u5c5e\u6027\u89c2\u5bdf\u5668\u3002<\/p>\n
      \n
      \u6ce8\u610f\uff1a
      \u4e0d\u9700\u8981\u4e3a\u65e0\u6cd5\u91cd\u8f7d\u7684\u8ba1\u7b97\u5c5e\u6027\u6dfb\u52a0\u5c5e\u6027\u89c2\u5bdf\u5668\uff0c\u56e0\u4e3a\u53ef\u4ee5\u901a\u8fc7 setter \u76f4\u63a5\u76d1\u63a7\u548c\u54cd\u5e94\u503c\u7684\u53d8\u5316\u3002  <\/p>\n<\/blockquote>\n
      \u53ef\u4ee5\u4e3a\u5c5e\u6027\u6dfb\u52a0\u5982\u4e0b\u7684\u4e00\u4e2a\u6216\u5168\u90e8\u89c2\u5bdf\u5668\uff1a<\/p>\n