{"rsdb":{"rid":"351751","subhead":"","postdate":"0","aid":"249690","fid":"90","uid":"1","topic":"1","content":"
\n

Scala\u89e3\u91ca\u5668\u7684\u4f7f\u7528<\/span><\/strong><\/h3> \n

 <\/p> \n

·REPL<\/span>\uff1a<\/span>Read<\/span>\uff08\u53d6\u503c\uff09<\/span>-> eva luation<\/span>\uff08\u6c42\u503c\uff09<\/span>-> Print<\/span>\uff08\u6253\u5370\uff09<\/span>-> Loop<\/span>\uff08\u5faa\u73af\uff09\u3002<\/span>scala<\/span>\u89e3\u91ca\u5668\u4e5f\u88ab\u79f0\u4e3a<\/span>REPL<\/span>\uff0c\u4f1a\u5feb\u901f\u7f16\u8bd1<\/span>scala<\/span>\u4ee3\u7801\u4e3a\u5b57\u8282\u7801\uff0c\u7136\u540e\u4ea4\u7ed9<\/span>JVM<\/span>\u6765\u6267\u884c\u3002<\/span><\/p> \n

 <\/p> \n

·\u8ba1\u7b97\u8868\u8fbe\u5f0f\uff1a\u5728scala><\/span>\u547d\u4ee4\u884c\u5185\uff0c\u952e\u5165<\/span>scala<\/span>\u4ee3\u7801\uff0c\u89e3\u91ca\u5668\u4f1a\u76f4\u63a5\u8fd4\u56de\u7ed3\u679c\u7ed9\u4f60\u3002\u5982\u679c\u4f60\u6ca1\u6709\u6307\u5b9a\u53d8\u91cf\u6765\u5b58\u653e\u8fd9\u4e2a\u503c\uff0c\u90a3\u4e48\u503c\u9ed8\u8ba4\u7684\u540d\u79f0\u4e3a<\/span>res<\/span>\uff0c\u800c\u4e14\u4f1a\u663e\u793a\u7ed3\u679c\u7684\u6570\u636e\u7c7b\u578b\uff0c\u6bd4\u5982<\/span>Int<\/span>\u3001<\/span>Double<\/span>\u3001<\/span>String<\/span>\u7b49\u7b49\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0c\u8f93\u51651 + 1<\/span>\uff0c\u4f1a\u770b\u5230<\/span>res0: Int = 2<\/span><\/p> \n

 <\/p> \n

·\u5185\u7f6e\u53d8\u91cf\uff1a\u5728\u540e\u9762\u53ef\u4ee5\u7ee7\u7eed\u4f7f\u7528res<\/span>\u8fd9\u4e2a\u53d8\u91cf\uff0c\u4ee5\u53ca\u5b83\u5b58\u653e\u7684\u503c\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0c2.0 * res0<\/span>\uff0c\u8fd4\u56de<\/span>res1: Double = 4.0<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0c"Hi, " + res0<\/span>\uff0c\u8fd4\u56de<\/span>res2: String = Hi, 2<\/span><\/p> \n

 <\/p> \n

·\u81ea\u52a8\u8865\u5168\uff1a\u5728scala><\/span>\u547d\u4ee4\u884c\u5185\uff0c\u53ef\u4ee5\u4f7f\u7528<\/span>Tab<\/span>\u952e\u8fdb\u884c\u81ea\u52a8\u8865\u5168\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0c\u8f93\u5165res2.to<\/span>\uff0c\u6572\u51fb<\/span>Tab<\/span>\u952e\uff0c\u89e3\u91ca\u5668\u4f1a\u663e\u793a\u51fa\u4ee5\u4e0b\u9009\u9879\uff0c<\/span>toCharArray<\/span>\uff0c<\/span>toLowerCase<\/span>\uff0c<\/span>toString<\/span>\uff0c<\/span>toUpperCase<\/span>\u3002\u56e0\u4e3a\u6b64\u65f6\u65e0\u6cd5\u5224\u5b9a\u4f60\u9700\u8981\u8865\u5168\u7684\u662f\u54ea\u4e00\u4e2a\uff0c\u56e0\u6b64\u4f1a\u63d0\u4f9b\u7ed9\u4f60\u6240\u6709\u7684\u9009\u9879\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0c\u8f93\u5165res2.toU<\/span>\uff0c\u6572\u51fb<\/span>Tab<\/span>\u952e\uff0c\u76f4\u63a5\u4f1a\u7ed9\u4f60\u8865\u5168\u4e3a<\/span>res2.toUpperCase<\/span>\u3002<\/span><\/p> \n

 <\/p> \n

 <\/p> \n

Scala\u58f0\u660e\u53d8\u91cf<\/span><\/strong><\/h3> \n

 val \u4ee3\u8868\u5e38\u91cf
\u3000\u3000val a=100;
 var \u4ee3\u8868\u53d8\u91cf
\u3000\u3000var a=100;<\/p> \n

 <\/p> \n

·\u58f0\u660eval<\/span>\u53d8\u91cf\uff1a\u53ef\u4ee5\u58f0\u660e<\/span>val<\/span>\u53d8\u91cf\u6765\u5b58\u653e\u8868\u8fbe\u5f0f\u7684\u8ba1\u7b97\u7ed3\u679c\u3002<\/span><\/p> \n

·\u4f8b\u5982\uff0cval result = 1 + 1<\/span><\/p> \n

·\u540e\u7eed\u8fd9\u4e9b\u5e38\u91cf\u662f\u53ef\u4ee5\u7ee7\u7eed\u4f7f\u7528\u7684\uff0c\u4f8b\u5982\uff0c2 * result<\/span><\/p> \n

·\u4f46\u662f\u5e38\u91cf\u58f0\u660e\u540e\uff0c\u662f\u65e0\u6cd5\u6539\u53d8\u5b83\u7684\u503c\u7684\uff0c\u4f8b\u5982\uff0cresult = 1<\/span>\uff0c\u4f1a\u8fd4\u56de<\/span>error: reassignment to val<\/span>\u7684\u9519\u8bef\u4fe1\u606f\u3002<\/span><\/p> \n

·\u58f0\u660evar<\/span>\u53d8\u91cf\uff1a\u5982\u679c\u8981\u58f0\u660e\u503c\u53ef\u4ee5\u6539\u53d8\u7684\u5f15\u7528\uff0c\u53ef\u4ee5\u4f7f\u7528<\/span>var<\/span>\u53d8\u91cf\u3002<\/span><\/p> \n

·\u4f8b\u5982\uff0cval myresult = 1<\/span>\uff0c<\/span>myresult = 2<\/span><\/p> \n

·\u4f46\u662f\u5728scala<\/span>\u7a0b\u5e8f\u4e2d\uff0c\u901a\u5e38\u5efa\u8bae\u4f7f\u7528<\/span>val<\/span>\uff0c\u4e5f\u5c31\u662f\u5e38\u91cf\uff0c\u56e0\u6b64\u6bd4\u5982\u7c7b\u4f3c\u4e8e<\/span>spark<\/span>\u7684\u5927\u578b\u590d\u6742\u7cfb\u7edf\u4e2d\uff0c\u9700\u8981\u5927\u91cf\u7684\u7f51\u7edc\u4f20\u8f93\u6570\u636e\uff0c\u5982\u679c\u4f7f\u7528<\/span>var<\/span>\uff0c\u53ef\u80fd\u4f1a\u62c5\u5fc3\u503c\u88ab\u9519\u8bef\u7684\u66f4\u6539\u3002<\/span><\/p> \n

·\u5728Java<\/span>\u7684\u5927\u578b\u590d\u6742\u7cfb\u7edf\u7684\u8bbe\u8ba1\u548c\u5f00\u53d1\u4e2d\uff0c\u4e5f\u4f7f\u7528\u4e86\u7c7b\u4f3c\u7684\u7279\u6027\uff0c\u6211\u4eec\u901a\u5e38\u4f1a\u5c06\u4f20\u9012\u7ed9\u5176\u4ed6\u6a21\u5757 <\/span>\/ <\/span>\u7ec4\u4ef6 <\/span>\/ <\/span>\u670d\u52a1\u7684\u5bf9\u8c61\uff0c\u8bbe\u8ba1\u6210\u4e0d\u53ef\u53d8\u7c7b\uff08<\/span>Immutable Class<\/span>\uff09\u3002\u5728\u91cc\u9762\u4e5f\u4f1a\u4f7f\u7528<\/span>java<\/a><\/span>\u7684\u5e38\u91cf\u5b9a\u4e49\uff0c\u6bd4\u5982<\/span>final<\/span>\uff0c\u963b\u6b62\u53d8\u91cf\u7684\u503c\u88ab\u6539\u53d8\u3002\u4ece\u800c\u63d0\u9ad8\u7cfb\u7edf\u7684\u5065\u58ee\u6027\uff08<\/span>robust<\/span>\uff0c\u9c81\u68d2\u6027\uff09\uff0c\u548c\u5b89\u5168\u6027\u3002<\/span><\/p> \n

·\u6307\u5b9a\u7c7b\u578b\uff1a\u65e0\u8bba\u58f0\u660eval<\/span>\u53d8\u91cf\uff0c\u8fd8\u662f\u58f0\u660e<\/span>var<\/span>\u53d8\u91cf\uff0c\u90fd\u53ef\u4ee5\u624b\u52a8\u6307\u5b9a\u5176\u7c7b\u578b\uff0c\u5982\u679c\u4e0d\u6307\u5b9a\u7684\u8bdd\uff0c<\/span>scala<\/span>\u4f1a\u81ea\u52a8\u6839\u636e\u503c\uff0c\u8fdb\u884c\u7c7b\u578b\u7684\u63a8\u65ad\u3002<\/span><\/p> \n

·\u4f8b\u5982\uff0cval name: String = null<\/span><\/p> \n

·\u4f8b\u5982\uff0cval name: Any = "leo"<\/span><\/p> \n

·\u58f0\u660e\u591a\u4e2a\u53d8\u91cf\uff1a\u53ef\u4ee5\u5c06\u591a\u4e2a\u53d8\u91cf\u653e\u5728\u4e00\u8d77\u8fdb\u884c\u58f0\u660e\u3002<\/p> \n

·\u4f8b\u5982\uff0cval name1, name2:String = null<\/span><\/p> \n

·\u4f8b\u5982\uff0cval num1, num2 = 100<\/span><\/p> \n

 <\/p> \n

 <\/p> \n

 <\/p> \n

Scala\u6570\u636e\u7c7b\u578b\u4e0e\u64cd\u4f5c\u7b26<\/span><\/strong><\/h3> \n

·\u57fa\u672c\u6570\u636e\u7c7b\u578b\uff1aByte<\/span>\u3001<\/span>Char<\/span>\u3001<\/span>Short<\/span>\u3001<\/span>Int<\/span>\u3001<\/span>Long<\/span>\u3001<\/span>Float<\/span>\u3001<\/span>Double<\/span>\u3001<\/span>Boolean<\/span>\u3002<\/span><\/p> \n

 <\/p> \n

·\u4e4d\u4e00\u770b\u4e0eJava<\/span>\u7684\u57fa\u672c\u6570\u636e\u7c7b\u578b\u7684\u5305\u88c5\u7c7b\u578b\u76f8\u540c\uff0c\u4f46\u662f<\/span>scala<\/span>\u6ca1\u6709\u57fa\u672c\u6570\u636e\u7c7b\u578b\u4e0e\u5305\u88c5\u7c7b\u578b\u7684\u6982\u5ff5\uff0c\u7edf\u4e00\u90fd\u662f\u7c7b\u3002<\/span>scala<\/span>\u81ea\u5df1\u4f1a\u8d1f\u8d23\u57fa\u672c\u6570\u636e\u7c7b\u578b\u548c\u5f15\u7528\u7c7b\u578b\u7684\u8f6c\u6362\u64cd\u4f5c\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f7f\u7528\u4ee5\u4e0a\u7c7b\u578b\uff0c\u76f4\u63a5\u5c31\u53ef\u4ee5\u8c03\u7528\u5927\u91cf\u7684\u51fd\u6570\uff0c\u4f8b\u5982\uff0c1.toString()<\/span>\uff0c<\/span>1.to(10)<\/span>\u3002<\/span><\/p> \n

 <\/p> \n

·\u7c7b\u578b\u7684\u52a0\u5f3a\u7248\u7c7b\u578b\uff1ascala<\/span>\u4f7f\u7528\u5f88\u591a\u52a0\u5f3a\u7c7b\u7ed9\u6570\u636e\u7c7b\u578b\u589e\u52a0\u4e86\u4e0a\u767e\u79cd\u589e\u5f3a\u7684\u529f\u80fd\u6216\u51fd\u6570\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0cString<\/span>\u7c7b\u901a\u8fc7<\/span>StringOps<\/span>\u7c7b\u589e\u5f3a\u4e86\u5927\u91cf\u7684\u51fd\u6570\uff0c<\/span>"Hello".intersect(" World")<\/span>\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0cScala<\/span>\u8fd8\u63d0\u4f9b\u4e86<\/span>RichInt<\/span>\u3001<\/span>RichDouble<\/span>\u3001<\/span>RichChar<\/span>\u7b49\u7c7b\u578b\uff0c<\/span>RichInt<\/span>\u5c31\u63d0\u4f9b\u4e86<\/span>to<\/span>\u51fd\u6570\uff0c<\/span>1.to(10)<\/span>\uff0c\u6b64\u5904<\/span>Int<\/span>\u5148\u9690\u5f0f\u8f6c\u6362\u4e3a<\/span>RichInt<\/span>\uff0c\u7136\u540e\u518d\u8c03\u7528\u5176<\/span>to<\/span>\u51fd\u6570<\/span><\/p> \n

 <\/p> \n

·\u57fa\u672c\u64cd\u4f5c\u7b26\uff1ascala<\/span>\u7684\u7b97\u672f\u64cd\u4f5c\u7b26\u4e0e<\/span>java<\/a><\/span>\u7684\u7b97\u672f\u64cd\u4f5c\u7b26\u4e5f\u6ca1\u6709\u4ec0\u4e48\u533a\u522b\uff0c\u6bd4\u5982<\/span>+<\/span>\u3001<\/span>-<\/span>\u3001<\/span>*<\/span>\u3001<\/span>\/<\/span>\u3001<\/span>%<\/span>\u7b49\uff0c\u4ee5\u53ca<\/span>&<\/span>\u3001<\/span>|<\/span>\u3001<\/span>^<\/span>\u3001<\/span>>><\/span>\u3001<\/span><<<\/span>\u7b49\u3002<\/span><\/p> \n

 <\/p> \n

·\u4f46\u662f\uff0c\u5728scala<\/span>\u4e2d\uff0c\u8fd9\u4e9b\u64cd\u4f5c\u7b26\u5176\u5b9e\u662f\u6570\u636e\u7c7b\u578b\u7684\u51fd\u6570\uff0c\u6bd4\u5982<\/span>1 + 1<\/span>\uff0c\u53ef\u4ee5\u5199\u505a<\/span>1.+(1)<\/span><\/p> \n

 <\/p> \n

·\u4f8b\u5982\uff0c1.to(10)<\/span>\uff0c\u53c8\u53ef\u4ee5\u5199\u505a<\/span>1 to 10<\/span><\/p> \n

 <\/p> \n

·scala<\/span>\u4e2d\u6ca1\u6709\u63d0\u4f9b<\/span>++<\/span>\u3001<\/span>--<\/span>\u64cd\u4f5c\u7b26\uff0c\u6211\u4eec\u53ea\u80fd\u4f7f\u7528<\/span>+<\/span>\u548c<\/span>-<\/span>\uff0c\u6bd4\u5982<\/span>counter = 1<\/span>\uff0c<\/span>counter++<\/span>\u662f\u9519\u8bef\u7684\uff0c\u5fc5\u987b\u5199\u505a<\/span>counter += 1.<\/span><\/p> \n

 <\/p> \n

 <\/p> \n

Scala<\/strong> <\/strong>\u51fd\u6570\u8c03\u7528\u4e0e<\/span>apply()\u51fd\u6570<\/span><\/strong><\/h3> \n

·\u51fd\u6570\u8c03\u7528\u65b9\u5f0f\uff1a\u5728scala<\/span>\u4e2d\uff0c\u51fd\u6570\u8c03\u7528\u4e5f\u5f88\u7b80\u5355\u3002<\/span><\/p> \n

·\u4f8b\u5982\uff0cimport scala.math._<\/span>\uff0c<\/span>sqrt(2)<\/span>\uff0c<\/span>pow(2, 4)<\/span>\uff0c<\/span>min(3, Pi)<\/span>\u3002<\/span><\/p> \n

·\u4e0d\u540c\u7684\u4e00\u70b9\u662f\uff0c\u5982\u679c\u8c03\u7528\u51fd\u6570\u65f6\uff0c\u4e0d\u9700\u8981\u4f20\u9012\u53c2\u6570\uff0c\u5219scala<\/span>\u5141\u8bb8\u8c03\u7528\u51fd\u6570\u65f6\u7701\u7565\u62ec\u53f7\u7684\uff0c\u4f8b\u5982\uff0c<\/span>"Hello World".distinct<\/span><\/p> \n

 <\/p> \n

·apply<\/span>\u51fd\u6570<\/span><\/p> \n

·Scala<\/span>\u4e2d\u7684<\/span>apply<\/span>\u51fd\u6570\u662f\u975e\u5e38\u7279\u6b8a\u7684\u4e00\u79cd\u51fd\u6570\uff0c\u5728<\/span>Scala<\/span>\u7684<\/span>object<\/span>\u4e2d\uff0c\u53ef\u4ee5\u58f0\u660e<\/span>apply<\/span>\u51fd\u6570\u3002\u800c\u4f7f\u7528\u201c\u7c7b\u540d<\/span>()<\/span>\u201d\u7684\u5f62\u5f0f\uff0c\u5176\u5b9e\u5c31\u662f\u201c\u7c7b\u540d<\/span>.apply()<\/span>\u201d\u7684\u4e00\u79cd\u7f29\u5199\u3002\u901a\u5e38\u4f7f\u7528\u8fd9\u79cd\u65b9\u5f0f\u6765\u6784\u9020\u7c7b\u7684\u5bf9\u8c61\uff0c\u800c\u4e0d\u662f\u4f7f\u7528\u201c<\/span>new <\/span>\u7c7b\u540d<\/span>()<\/span>\u201d\u7684\u65b9\u5f0f\u3002<\/span><\/p> \n

·\u4f8b\u5982\uff0c"Hello World"(6)<\/span>\uff0c\u56e0\u4e3a\u5728<\/span>StringOps<\/span>\u7c7b\u4e2d\u6709<\/span>def apply(n: Int): Char<\/span>\u7684\u51fd\u6570\u5b9a\u4e49\uff0c\u6240\u4ee5<\/span>"Hello World"(6)<\/span>\uff0c\u5b9e\u9645\u4e0a\u662f<\/span>"Hello World".apply(6)<\/span>\u7684\u7f29\u5199\u3002<\/span><\/p> \n

·\u4f8b\u5982\uff0cArray(1, 2, 3, 4)<\/span>\uff0c\u5b9e\u9645\u4e0a\u662f\u7528<\/span>Array object<\/span>\u7684<\/span>apply()<\/span>\u51fd\u6570\u6765\u521b\u5efa<\/span>Array<\/span>\u7c7b\u7684\u5b9e\u4f8b\uff0c\u4e5f\u5c31\u662f\u4e00\u4e2a\u6570\u7ec4\u3002<\/span><\/p> \n

 <\/p> \n<\/div>","orderid":"0","title":"Scala \u57fa\u7840\u8bed\u6cd5","smalltitle":"","mid":"0","fname":"Scala","special_id":"0","bak_id":"0","info":"0","hits":"119","pages":"1","comments":"0","posttime":"2019-09-03 03:44:19","list":"1567453459","username":"admin","author":"","copyfrom":"","copyfromurl":"","titlecolor":"","fonttype":"0","titleicon":"0","picurl":"https:\/\/www.cppentry.com\/upload_files\/","ispic":"0","yz":"1","yzer":"","yztime":"0","levels":"0","levelstime":"0","keywords":"Scala<\/A> \u57fa\u7840<\/A> \u8bed\u6cd5<\/A>","jumpurl":"","iframeurl":"","style":"","template":"a:3:{s:4:\"head\";s:0:\"\";s:4:\"foot\";s:0:\"\";s:8:\"bencandy\";s:0:\"\";}","target":"0","ip":"120.229.33.54","lastfid":"0","money":"0","buyuser":"","passwd":"","allowdown":"","allowview":"","editer":"","edittime":"0","begintime":"0","endtime":"0","description":"Scala \u57fa\u7840\u8bed\u6cd5","lastview":"1713962139","digg_num":"0","digg_time":"0","forbidcomment":"0","ifvote":"0","heart":"","htmlname":"","city_id":"0"},"page":"1"}