{"id":339,"date":"2026-01-14T00:09:32","date_gmt":"2026-01-13T16:09:32","guid":{"rendered":"https:\/\/www.linerroom.cn\/?p=339"},"modified":"2026-01-14T19:18:33","modified_gmt":"2026-01-14T11:18:33","slug":"dart%e8%af%ad%e8%a8%80%ef%bc%88flutter%ef%bc%89%e7%ac%94%e8%ae%b0","status":"publish","type":"post","link":"https:\/\/www.linerroom.cn\/?p=339","title":{"rendered":"Dart\u8bed\u8a00\uff08flutter\uff09\u7b14\u8bb0"},"content":{"rendered":"\n

\u57fa\u7840\u7bc7<\/h2>\n\n\n\n
void main(List<String> args) {\n  \/\/\u53d8\u91cfvar\n  var age = 10;\n  print(age);\n  \n  \/\/\u5e38\u91cfconst\n  const pai = 3.1415926;\n  print(pai);\n\n  \/\/\u5e38\u91cffinal\n  final time =DateTime.now();\n  print(time);\n\n  \/\/\u5b57\u7b26\u4e32 String\n  String text = \"\u4e0d\u9519\";\n  text = \"\u6709\u9519\";\n  print(text);\n  print(\"\u6211\u8981\u5728${DateTime.now()}\u65f6\u95f4\u5403\u996d\");\n  print(\"\u4f60\u6709\u9519\u6ca1\uff1f\u6211$text\");\n\n  \/\/Dart\u4e2d\u7684\u6570\u5b57\u7c7b\u578b-int\/num\/double\n  int a = 2 ;\n  num b = 1.5;\n  double c = 1.5;\n  a = c.toInt();\/\/\u4e0d\u96be\u76f4\u63a5\u8d4b\u503ca=c\n  c = a.toDouble();\n  b  = a ;\n  b  = c ;\n  var aa= a+b+c;\n  print(aa);\n\n  \/\/\u5e03\u5c14 bool\n  bool a1 = false;\n  bool a2 = true ;\n  print(a1);\n  print(a2); \n\n  \/\/---------------------------------------------------------------------\n\n  \/\/\u5217\u8868list\n  List students = [1,2,3,4,5];\n  print(students);\n  List students1 = [31,312,4234,4123];\n  print(students1);\n  students.add(\"6\");\/\/\u5c3e\u90e8\u6dfb\u52a0\n  students.add(students1);\/\/\u5c3e\u90e8\u6dfb\u52a0\u5217\u8868\n  students.remove(1);\/\/\u5220\u9664\u7b26\u5408\u6761\u4ef6\u7684\n  students.removeLast();\/\/\u5220\u9664\u6700\u540e\u4e00\u4e2a\n  students.removeRange(0, 3);\/\/\u5220\u9664\u8303\u56f4\u503c\n  \/\/\u64cd\u4f5c\u5217\u8868\n  List students2 = [\"\u5f20\u4e09\",\"\u674e\u56db\",\"\u674e\u4e94\",\"\u8d75\u516d\"];\n\n  students2.forEach((item){\n    print(item);\n  });\/\/\u8f93\u51fa\u5f20\u4e09\u674e\u56db\u674e\u4e94\u8d75\u516d\n\n  print(\n    students2.every((item){\n      return item.startsWith(\"\u674e\");\/\/\u8fd4\u56de\u662f\u4e0d\u662f\u90fd\u662f\u59d3\u674e\u7684\uff0c\u90fd\u662f\u59d3\u674e\u4e3a\u771f\uff0c\u53cd\u4e4b\u4e3a\u5047\u3002\n    })\n  );\/\/\u8f93\u51fafalse\n\n  print(\n    students2.any((item){\n      return item.startsWith(\"\u674e\");\/\/\u8fd4\u56de\u662f\u4e0d\u662f\u6709\u4e00\u4e2a\u59d3\u674e\u7684\uff0c\u6709\u4e00\u4e2a\u59d3\u674e\u4e3a\u771f\uff0c\u53cd\u4e4b\u4e3a\u5047\u3002\n    })\n  );\/\/\u8f93\u51fatrue\n\n  print(\n    students2.map((item){\n      return item.startsWith(\"\u674e\");\/\/\u8fd4\u56de\u662f\u4e0d\u662f\u6709\u4e00\u4e2a\u59d3\u674e\u7684\uff0c\u6709\u4e00\u4e2a\u59d3\u674e\u4e3a\u771f\uff0c\u53cd\u4e4b\u4e3a\u5047\u3002\n    })\n  );\/\/\u8f93\u51fa[false, true, true, false]\n\n  students2.where((item){\n      return item.startsWith(\"\u674e\");\/\/\u8fd4\u56de\u6240\u6709\u59d3\u674e\u7684\n    }).toList();\/\/\u8f93\u51fa[\u674e\u56db, \u674e\u4e94]\n  \n  \/\/\u5217\u8868\u5c5e\u6027\n  print(students2.length);\/\/\u8f93\u51fa4 \u957f\u5ea6\n  print(students2.first);\/\/\u8f93\u51fa\u5f20\u4e09 \u9996\u4e2a\u5143\u7d20\n  print(students2.last);\/\/\u8f93\u51fa\u8d75\u516d  \u6700\u540e\u5143\u7d20\n  print(students2.isEmpty);\/\/\u8f93\u51fafalse  \u662f\u5426\u4e3a\u7a7a\n  print(students2.isNotEmpty);\/\/\u8f93\u51fatrue  \u662f\u5426\u4e0d\u4e3a\u7a7a\n  print(students2.indexOf(\"\u674e\u56db\"));\/\/\u8f93\u51fa1  \u7b2c\u4e00\u4e2a\u674e\u56db\u7684\u7d22\u5f15\n  print(students2.contains(\"\u674e\u56db\"));\/\/\u8f93\u51fatrue  \u662f\u5426\u5305\u542b\u674e\u56db\n  print(students2.reversed);\/\/\u8f93\u51fa(\u8d75\u516d, \u674e\u4e94, \u674e\u56db, \u5f20\u4e09)  \u53cd\u8f6c\n  print(students2.sublist(0, 2));\/\/\u8f93\u51fa[\u5f20\u4e09, \u674e\u56db]  \u622a\u53d6\u5b50\u5217\u8868\n  print(students2.sublist(2));\/\/\u8f93\u51fa[\u674e\u4e94, \u8d75\u516d]  \u622a\u53d6\u5b50\u5217\u8868\u4ece\u7d22\u5f152\u5f00\u59cb\u5230\u7ed3\u675f\n  print(students2.sublist(2, 4));\/\/\u8f93\u51fa[\u674e\u4e94, \u8d75\u516d]  \u622a\u53d6\u5b50\u5217\u8868\u4ece\u7d22\u5f152\u5f00\u59cb\u5230\u7d22\u5f154\u7ed3\u675f\n  print(students2.sublist(2, 2));\/\/\u8f93\u51fa[]  \u622a\u53d6\u5b50\u5217\u8868\u4ece\u7d22\u5f152\u5f00\u59cb\u5230\u7d22\u5f152\u7ed3\u675f\uff0c\u4e0d\u5305\u542b\u7d22\u5f152\n\n  \/\/---------------------------------------------------------------------\n\n  \/\/\u5b57\u5178map {key:value}\n  Map map = {\"name\":\"\u5f20\u4e09\",\"age\":10};\n  Map map1 = {\"name\":\"\u738b\u4e8c\",\"age\":11};\n  print(map[\"name\"]);\/\/\u8f93\u51fa\u5f20\u4e09\n  print(map[\"age\"]);\/\/\u8f93\u51fa10\n  map[\"age\"] = 11;\/\/\u4fee\u6539\u503c\n  map.remove(\"age\");\/\/\u5220\u9664\u952e\u503c\u5bf9\n\n  map.forEach((key, value) {\n    print(\"$key:$value\");\/\/\u904d\u5386\u5168\u90e8\u952e\u503c\u5bf9\n  });\/\/\u8f93\u51faname:\u5f20\u4e09\n\n  map.addAll(map1);\/\/\u5408\u5e76map1\u5230map\n  print(map);\/\/\u8f93\u51fa{\"name\":\"\u5f20\u4e09\",\"age\":10,\"name\":\"\u738b\u4e8c\",\"age\":11}\n\n  print(map.containsKey(\"name\"));\/\/\u8f93\u51fatrue  \u662f\u5426\u5305\u542b\u952ename\n  print(map.containsValue(\"\u5f20\u4e09\"));\/\/\u8f93\u51fatrue  \u662f\u5426\u5305\u542b\u503c\u5f20\u4e09\n  \n  map.clear();\/\/\u6e05\u7a7amap\n  print(map);\/\/\u8f93\u51fa{}\n\n  \/\/---------------------------------------------------------------------\n  \n  \/\/Dart\u4e2d\u7684\u52a8\u6001\u7c7b\u578b-dynamic\n  dynamic a3 = 10;\n  print(a3);\n  a3 = \"\u4f60\u597d\";\n  print(a3);\n  a3 = true;\n  print(a3);\n\n  \/\/\u7a7a\u5b89\u5168\u64cd\u4f5c\u7b26   ?\u53ef\u7a7a\u7c7b\u578b   ?.\u5b89\u5168\u8bbf\u95ee   !.\u975e\u7a7a\u65ad\u8a00   ?? \u7a7a\u5408\u5e76\n  String? nameaa = null;\n  nameaa?.substring(0, 1);\/\/\u5b89\u5168\u8bbf\u95ee(\u5ba2\u89c2)\n  nameaa!.substring(0, 1);\/\/\u975e\u7a7a\u65ad\u8a00(\u4e3b\u89c2-\u5f00\u53d1\u8005\u8ba4\u4e3a\u4e00\u5b9a\u4f46\u62a5\u9519\u8fd8\u5f97\u62a5\u9519)\n  \n  String name1 = nameaa ?? \"\u9ed8\u8ba4\u503c\";\/\/\u7a7a\u5408\u5e76\n  print(name1);\/\/\u8f93\u51fa\u9ed8\u8ba4\u503c\n\n  \/\/\u5355\u5206\u652f \u53cc\u5206\u652f \u591a\u5206\u652f\n  int aaa = 10;\n  if(aaa > 0){\n    print(\"\u5927\u4e8e0\");\n  }\n  int aaa1 = 10;\n  if(aaa1 > 0){\n    print(\"\u5927\u4e8e0\");\n  }else{\n    print(\"\u5c0f\u4e8e\u7b49\u4e8e0\");\n  }\n  int aaa2 = 10;\n  if(aaa2 > 0){\n    print(\"\u5927\u4e8e0\");\n  }else if(aaa2 == 0){\n    print(\"\u7b49\u4e8e0\");\n  }else{\n    print(\"\u5c0f\u4e8e0\");\n  }\n\n  \/\/\u4e09\u76ee\u8fd0\u7b97\u7b26\n  int aaa3 = 10;\n  String result = aaa3 > 0 ? \"\u5927\u4e8e0\" : \"\u5c0f\u4e8e\u7b49\u4e8e0\";\n  print(result);\/\/\u8f93\u51fa\u5927\u4e8e0\n\n  \/\/switch\u8bed\u53e5\n  int aaa4 = 10;\n  switch(aaa4){\n    case 1:\n      print(\"1\");\n      break;\n    case 2:\n      print(\"2\");\n      break;\n    default:\n      print(\"\u5176\u4ed6\");\n  }\n\n  \/\/while\u5faa\u73af continue\u548cbreak\n  int aaa5 = 10;\n  while(aaa5 > 0){\n    if(aaa5 == 5){\n      continue;\/\/\u8df3\u8fc75\n    }\n    print(aaa5);\n    aaa5--;\n  }\n\n  \/\/for\u5faa\u73af\n  for(int i = 0;i<10;i++){\n    print(i);\n  }\n\n  \/\/\u51fd\u6570\u5b9a\u4e49\n  int add(int ad,int ba){\/\/\u6709\u8fd4\u56de\u503c\u7684\u5b9a\u4e49\n    return ad+ba;\n  }\n  void printInfo(String name,int age){\/\/\u65e0\u8fd4\u56de\u503c\u7684\u5b9a\u4e49\n    print(\"\u59d3\u540d:$name,\u5e74\u9f84:$age\");\n  }\n  getvalue(){\n    return \"123\";\n  }\n}\n\n<\/code><\/pre>\n\n\n\n
\u8bf4\u660e<\/span><\/i><\/div>
\u8fd9\u6bb5\u4ee3\u7801\u662f Dart \u5165\u95e8\u7684\u300c\u8bed\u6cd5\u901f\u67e5\u8868\u300d\uff0c\u628a\u53d8\u91cf\u58f0\u660e\u3001\u6570\u636e\u7c7b\u578b\u3001\u5217\u8868 \/ \u5b57\u5178\u64cd\u4f5c\u3001\u6761\u4ef6\u5224\u65ad\u3001\u5faa\u73af\u3001\u51fd\u6570\u5b9a\u4e49\u7b49\u57fa\u7840\u77e5\u8bc6\u70b9\u90fd\u7528\u793a\u4f8b\u4ee3\u7801\u5b9e\u73b0\u4e86\u4e00\u904d\uff0c\u8dd1\u8d77\u6765\u80fd\u76f4\u89c2\u770b\u5230\u6bcf\u4e2a\u8bed\u6cd5\u7684\u6548\u679c\u3002

\u8fd9\u6bb5\u4ee3\u7801\u8986\u76d6\u4e86 Dart \u5165\u95e8\u7684\u6240\u6709\u6838\u5fc3\u8bed\u6cd5\uff0c\u91cd\u70b9\u662f\u53d8\u91cf \/ \u5e38\u91cf\u3001List\/Map \u64cd\u4f5c\u3001\u7a7a\u5b89\u5168\u3001\u6d41\u7a0b\u63a7\u5236\u3001\u51fd\u6570<\/strong>\uff1b
Dart \u662f\u5f3a\u7c7b\u578b\u8bed\u8a00\uff08\u867d\u7136\u6709 var\/dynamic<\/code> \u4f46\u63a8\u8350\u663e\u5f0f\u6307\u5b9a\u7c7b\u578b\uff09\uff0c\u7a7a\u5b89\u5168\u662f Dart \u7684\u7279\u8272\uff0c\u5fc5\u987b\u638c\u63e1 ?\/?. \/??<\/code>\uff1b
List \u7684 every\/any\/map\/where<\/code> \u548c Map \u7684\u952e\u503c\u5bf9\u64cd\u4f5c\u662f\u65e5\u5e38\u5f00\u53d1\u6700\u5e38\u7528\u7684\u5bb9\u5668\u65b9\u6cd5\u3002<\/div><\/div>\n\n\n\n
void main(List<String> args) {\n  print(command(\"add\",\"1\"));\/\/\u8f93\u51faadd1\n  showPerson(\"\u5f20\u4e09\",age: 10,sex: \"\u7537\");\/\/\u8f93\u51fa\u59d3\u540d:\u5f20\u4e09,\u5e74\u9f84:10,\u6027\u522b:\u7537\n  showInfo(text);\/\/\u8f93\u51fa\u6211\u662ftext\u51fd\u6570\n  print(add(1,2));\/\/\u8f93\u51fa3\n\n}\n\nFunction text = (){\n  print(\"\u6211\u662ftext\u51fd\u6570\");\n};\n\nvoid showInfo(Function f){\n  f();\n}\nint add(int a,int b)=>a+b;\/\/\u7bad\u5934\u51fd\u6570\uff0c\u8fd4\u56dea+b\nString command(String a,[String? b = \"12\",String? c]){\/\/\u53ef\u9009\u53c2\u6570\n    return a+ (b ?? \"\")+ (c ?? \"\");\n}\nshowPerson(String name,{int? age,String? sex}){\/\/\u547d\u540d\u53c2\u6570\n  print(\"\u59d3\u540d:$name,\u5e74\u9f84:$age,\u6027\u522b:$sex\");\n}\n\n<\/code><\/pre>\n\n\n\n
\u8bf4\u660e<\/span><\/i><\/div>
\u8fd9\u6bb5\u4ee3\u7801\u7684\u6838\u5fc3\u662f\u6f14\u793a Dart \u51fd\u6570\u7684\u591a\u79cd\u5b9a\u4e49\u548c\u8c03\u7528\u65b9\u5f0f\uff0c\u5305\u62ec\uff1a\u7b80\u5316\u5199\u6cd5\u7684\u7bad\u5934\u51fd\u6570\u3001\u53ef\u4f20\u53ef\u4e0d\u4f20\u7684\u53ef\u9009\u53c2\u6570\u3001\u5e26\u53c2\u6570\u540d\u7684\u547d\u540d\u53c2\u6570\uff0c\u4ee5\u53ca\u628a\u51fd\u6570\u5f53\u4f5c\u53d8\u91cf \/ \u53c2\u6570\u4f20\u9012\u7684\u7528\u6cd5\uff0c\u6240\u6709\u903b\u8f91\u90fd\u5728\u5165\u53e3\u51fd\u6570 main<\/code> \u91cc\u4f9d\u6b21\u8c03\u7528\u6267\u884c\u3002

Dart \u51fd\u6570\u7684\u53c2\u6570\u5206\u5fc5\u9009<\/strong>\u3001\u53ef\u9009\uff08[]\uff09<\/strong>\u3001\u547d\u540d\uff08{}\uff09<\/strong> \u4e09\u79cd\uff0c\u53ef\u9009\u53c2\u6570\u53ef\u8bbe\u9ed8\u8ba4\u503c\uff0c\u547d\u540d\u53c2\u6570\u8c03\u7528\u65f6\u8981\u5199\u53c2\u6570\u540d\uff1b
\u7bad\u5934\u51fd\u6570\uff08=><\/code>\uff09\u9002\u5408\u903b\u8f91\u7b80\u5355\u7684\u51fd\u6570\uff0c\u662f\u666e\u901a\u51fd\u6570\u7684\u7b80\u5316\u5199\u6cd5\uff1b
Dart \u4e2d\u51fd\u6570\u53ef\u4ee5\u8d4b\u503c\u7ed9\u53d8\u91cf\uff0c\u4e5f\u80fd\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\u7ed9\u5176\u4ed6\u51fd\u6570\uff08\u51fd\u6570\u4e5f\u662f\u4e00\u79cd\u6570\u636e\u7c7b\u578b\uff09\u3002<\/div><\/div>\n\n\n\n
\u4ee3\u7801\u7ec6\u8282<\/h3>\n\n\n\n
\u53d8\u91cf\u4e0e\u5e38\u91cf\uff08\u6700\u57fa\u7840\u7684\u5b58\u6570\u636e\uff09<\/h4>\n\n\n\n
var age = 10;        \/\/ \u53d8\u91cf\uff1a\u53ef\u4ee5\u968f\u65f6\u6539\u503c\uff0cDart \u81ea\u52a8\u8bc6\u522b\u7c7b\u578b\uff08\u8fd9\u91cc\u662fint\uff09\nconst pai = 3.1415926;\/\/ \u7f16\u8bd1\u65f6\u5e38\u91cf\uff1a\u503c\u5fc5\u987b\u5199\u6b7b\uff0c\u8fd0\u884c\u65f6\u4e0d\u80fd\u6539\uff08\u6bd4\u5982\u4e0d\u80fd\u7528DateTime.now()\uff09\nfinal time = DateTime.now();\/\/ \u8fd0\u884c\u65f6\u5e38\u91cf\uff1a\u503c\u53ef\u4ee5\u5728\u8fd0\u884c\u65f6\u786e\u5b9a\uff08\u6bd4\u5982\u5f53\u524d\u65f6\u95f4\uff09\uff0c\u4e00\u65e6\u8d4b\u503c\u5c31\u4e0d\u80fd\u6539<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\u533a\u522b\uff1avar \u662f \u201c\u53ef\u53d8\u7684\u76d2\u5b50\u201d\uff0cconst\/final \u662f \u201c\u5c01\u6b7b\u7684\u76d2\u5b50\u201d\uff08const \u66f4\u4e25\u683c\uff09\u3002<\/span><\/div>\n\n\n\n
\u5b57\u7b26\u4e32\uff08\u5b58\u6587\u5b57\uff09<\/h4>\n\n\n\n
String text = \"\u4e0d\u9519\";\ntext = \"\u6709\u9519\";\nprint(\"\u6211\u8981\u5728${DateTime.now()}\u65f6\u95f4\u5403\u996d\"); \/\/ \u5b57\u7b26\u4e32\u63d2\u503c\uff1a\u7528${}\u628a\u53d8\u91cf\/\u8868\u8fbe\u5f0f\u5d4c\u8fdb\u5b57\u7b26\u4e32\nprint(\"\u4f60\u6709\u9519\u6ca1\uff1f\u6211$text\"); \/\/ \u7b80\u5355\u53d8\u91cf\u53ef\u4ee5\u7701\u7565\u5927\u62ec\u53f7\uff0c\u6548\u679c\u548c\u4e0a\u9762\u4e00\u6837<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u5173\u952e\uff1aDart \u5b57\u7b26\u4e32\u7528\u53cc\u5f15\u53f7\uff0c\u63d2\u503c\u662f\u6700\u5e38\u7528\u7684\u62fc\u63a5\u65b9\u5f0f\uff0c\u6bd4 + \u53f7\u65b9\u4fbf\u3002<\/span><\/div>\n\n\n\n
\u6570\u5b57\u7c7b\u578b\uff08\u5b58\u6570\u5b57\uff09<\/h4>\n\n\n\n
int a = 2 ;     \/\/ \u6574\u6570\uff08\u53ea\u80fd\u5b58\u6574\u6570\uff0c\u6bd4\u59821\u300110\uff0c\u4e0d\u80fd\u5b581.5\uff09\nnum b = 1.5;    \/\/ \u901a\u7528\u6570\u5b57\uff08\u65e2\u80fd\u5b58\u6574\u6570\uff0c\u4e5f\u80fd\u5b58\u5c0f\u6570\uff09\ndouble c = 1.5; \/\/ \u5c0f\u6570\uff08\u53ea\u80fd\u5b58\u5e26\u5c0f\u6570\u70b9\u7684\u6570\uff09\na = c.toInt();  \/\/ \u5c0f\u6570\u8f6c\u6574\u6570\uff08\u4e0d\u4f1a\u76f4\u63a5\u8d4b\u503c\uff0c\u5fc5\u987b\u7528toInt()\uff09\nc = a.toDouble();\/\/ \u6574\u6570\u8f6c\u5c0f\u6570<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\uff1a\u4e0d\u540c\u6570\u5b57\u7c7b\u578b\u4e0d\u80fd\u76f4\u63a5\u8d4b\u503c\uff0c\u9700\u8981\u624b\u52a8\u8f6c\u6362\uff08\u6bd4\u5982 double \u4e0d\u80fd\u76f4\u63a5\u7ed9 int\uff09\u3002<\/span><\/div>\n\n\n\n
\u5e03\u5c14\u7c7b\u578b\uff08\u5b58\u771f\u5047\uff09<\/h4>\n\n\n\n
bool a1 = false; \/\/ \u5047\nbool a2 = true ; \/\/ \u771f<\/code><\/pre>\n\n\n\n
\n
<\/i><\/span>\u53ea\u6709 true\/false \u4e24\u4e2a\u503c\uff0c\u6ca1\u6709 \u201c0 \u4ee3\u8868\u5047\u3001\u975e 0 \u4ee3\u8868\u771f\u201d \u7684\u8bf4\u6cd5\uff08\u548c Java\/JS \u4e0d\u4e00\u6837\uff09\u3002<\/span><\/div>\n<\/div><\/div>\n\n\n\n
\n
\n
\n
\n
\u5217\u8868 List<\/h4>\n\n\n\n
List students = [1,2,3,4,5];\n\/\/ \u589e\u5220\u64cd\u4f5c\nstudents.add(\"6\");       \/\/ \u672b\u5c3e\u52a0\u4e00\u4e2a\u5143\u7d20\nstudents.remove(1);      \/\/ \u5220\u9664\u7b2c\u4e00\u4e2a\u7b49\u4e8e1\u7684\u5143\u7d20\nstudents.removeLast();   \/\/ \u5220\u9664\u6700\u540e\u4e00\u4e2a\u5143\u7d20\nstudents.removeRange(0,3);\/\/ \u5220\u9664\u7d22\u5f150\u52302\u7684\u5143\u7d20\uff08\u5de6\u95ed\u53f3\u5f00\uff0c\u4e0d\u5305\u542b3\uff09\n\n\/\/ \u904d\u5386\/\u5224\u65ad\u64cd\u4f5c\uff08\u91cd\u70b9\uff09\nstudents2.forEach((item)=>print(item)); \/\/ \u904d\u5386\u6bcf\u4e2a\u5143\u7d20\u5e76\u6253\u5370\nstudents2.every((item)=>item.startsWith(\"\u674e\")); \/\/ \u5224\u65ad\uff1a\u662f\u4e0d\u662f\u6240\u6709\u5143\u7d20\u90fd\u59d3\u674e\uff1f\uff08false\uff09\nstudents2.any((item)=>item.startsWith(\"\u674e\"));   \/\/ \u5224\u65ad\uff1a\u6709\u6ca1\u6709\u81f3\u5c11\u4e00\u4e2a\u59d3\u674e\uff1f\uff08true\uff09\nstudents2.map((item)=>item.startsWith(\"\u674e\"));   \/\/ \u8f6c\u6362\uff1a\u6bcf\u4e2a\u5143\u7d20\u8fd4\u56de\u201c\u662f\u5426\u59d3\u674e\u201d\u7684\u5e03\u5c14\u503c\nstudents2.where((item)=>item.startsWith(\"\u674e\")); \/\/ \u7b5b\u9009\uff1a\u53ea\u4fdd\u7559\u59d3\u674e\u7684\u5143\u7d20\n\n\/\/ \u5217\u8868\u5c5e\u6027\uff08\u67e5\u4fe1\u606f\uff09\nstudents2.length;    \/\/ \u957f\u5ea6\uff084\uff09\nstudents2.first;     \/\/ \u7b2c\u4e00\u4e2a\u5143\u7d20\uff08\u5f20\u4e09\uff09\nstudents2.last;      \/\/ \u6700\u540e\u4e00\u4e2a\u5143\u7d20\uff08\u8d75\u516d\uff09\nstudents2.indexOf(\"\u674e\u56db\"); \/\/ \u627e\u201c\u674e\u56db\u201d\u7684\u7d22\u5f15\uff081\uff09\nstudents2.sublist(0,2);    \/\/ \u622a\u53d6\u5b50\u5217\u8868\uff08\u7d22\u5f150\u52301\uff0c[\u5f20\u4e09,\u674e\u56db]\uff09<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\uff1a\u5217\u8868\u662f \u201c\u6709\u5e8f\u7684\u4e00\u7ec4\u6570\u636e\u201d\uff0c\u53ef\u4ee5\u589e\u5220\u6539\u67e5\uff0cevery\/any\/map\/where \u662f\u6700\u5e38\u7528\u7684\u64cd\u4f5c\u65b9\u6cd5\u3002<\/span><\/div>\n<\/div>\n<\/div>\n<\/div><\/div>\n<\/div><\/div>\n\n\n\n
\u5b57\u5178 Map\uff08\u5b58\u952e\u503c\u5bf9\uff0c\u6bd4\u5982 \u201c\u59d3\u540d – \u5f20\u4e09\u201d\uff09<\/h4>\n\n\n\n
Map map = {\"name\":\"\u5f20\u4e09\",\"age\":10};\nprint(map[\"name\"]);    \/\/ \u67e5\uff1a\u901a\u8fc7key\u53d6value\uff08\u5f20\u4e09\uff09\nmap[\"age\"] = 11;       \/\/ \u6539\uff1a\u4fee\u6539key\u5bf9\u5e94\u7684value\nmap.remove(\"age\");     \/\/ \u5220\uff1a\u5220\u9664\u67d0\u4e2a\u952e\u503c\u5bf9\nmap.forEach((k,v)=>print(\"$k:$v\")); \/\/ \u904d\u5386\uff1a\u6253\u5370\u6240\u6709key\u548cvalue\nmap.addAll(map1);      \/\/ \u5408\u5e76\uff1a\u628amap1\u7684\u5185\u5bb9\u52a0\u5230map\u91cc\nmap.containsKey(\"name\"); \/\/ \u5224\u65ad\uff1a\u6709\u6ca1\u6709name\u8fd9\u4e2akey\uff1f\uff08true\uff09\nmap.clear();           \/\/ \u6e05\u7a7a\uff1a\u5220\u9664\u6240\u6709\u952e\u503c\u5bf9<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\uff1aMap \u662f \u201c\u952e\u503c\u5bf9\u201d \u5f62\u5f0f\uff0ckey \u552f\u4e00\uff0c\u901a\u8fc7 key \u627e value \u6700\u5e38\u7528\u3002<\/span><\/div>\n\n\n\n
\u52a8\u6001\u7c7b\u578b & \u7a7a\u5b89\u5168\uff08Dart 2.12 + \u91cd\u70b9\uff09<\/h4>\n\n\n\n
dynamic a3 = 10;\na3 = \"\u4f60\u597d\"; \/\/ dynamic\u53ef\u4ee5\u968f\u4fbf\u6539\u7c7b\u578b\uff08\u4e0d\u63a8\u8350\uff0c\u5931\u53bb\u7c7b\u578b\u6821\u9a8c\uff09\n\nString? nameaa = null; \/\/ ?\uff1a\u8868\u793a\u8fd9\u4e2a\u53d8\u91cf\u53ef\u4ee5\u4e3a\u7a7a\nnameaa?.substring(0,1); \/\/ ?.\uff1a\u5b89\u5168\u8bbf\u95ee\uff0cnull\u7684\u8bdd\u4e0d\u6267\u884c\uff0c\u4e0d\u4f1a\u62a5\u9519\nnameaa!.substring(0,1); \/\/ !.\uff1a\u975e\u7a7a\u65ad\u8a00\uff0c\u5f00\u53d1\u8005\u4fdd\u8bc1\u975enull\uff0cnull\u7684\u8bdd\u4f1a\u62a5\u9519\nString name1 = nameaa ?? \"\u9ed8\u8ba4\u503c\"; \/\/ ??\uff1a\u7a7a\u5408\u5e76\uff0cnull\u7684\u8bdd\u7528\u9ed8\u8ba4\u503c<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u7a7a\u5b89\u5168\u6838\u5fc3\uff1a\u9632\u6b62 \u201c\u7a7a\u6307\u9488\u62a5\u9519\u201d\uff0c? \u5141\u8bb8\u4e3a\u7a7a\uff0c?. \u5b89\u5168\u8c03\u7528\uff0c?? \u7ed9\u9ed8\u8ba4\u503c\u3002<\/span><\/div>\n\n\n\n
\u6d41\u7a0b\u63a7\u5236\uff08\u4ee3\u7801\u7684 \u201c\u9009\u62e9 \/ \u5faa\u73af\u201d\uff09<\/h4>\n\n\n\n
\/\/ \u6761\u4ef6\u5224\u65ad\uff1aif\/\u4e09\u76ee\/switch\nif(aaa > 0) print(\"\u5927\u4e8e0\"); \/\/ \u5355\u5206\u652f\nString result = aaa3 > 0 ? \"\u5927\u4e8e0\" : \"\u5c0f\u4e8e\u7b49\u4e8e0\"; \/\/ \u4e09\u76ee\uff08\u7b80\u5316if-else\uff09\nswitch(aaa4){ \/\/ \u591a\u5206\u652f\u5339\u914d\n  case 1: print(\"1\"); break;\n  default: print(\"\u5176\u4ed6\");\n}\n\n\/\/ \u5faa\u73af\uff1awhile\/for\nwhile(aaa5 > 0){ \/\/ \u5148\u5224\u65ad\u6761\u4ef6\uff0c\u518d\u6267\u884c\n  if(aaa5 ==5) continue; \/\/ \u8df3\u8fc7\u5f53\u524d\u5faa\u73af\uff08\u4e0d\u6253\u53705\uff09\n  print(aaa5);\n  aaa5--;\n}\nfor(int i=0;i<10;i++) print(i); \/\/ \u56fa\u5b9a\u6b21\u6570\u5faa\u73af\uff08\u6253\u53700-9\uff09<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\uff1acontinue \u8df3\u8fc7\u672c\u6b21\u5faa\u73af\uff0cbreak \u7ec8\u6b62\u6574\u4e2a\u5faa\u73af\uff1bswitch \u8981\u52a0 break\uff0c\u5426\u5219\u4f1a \u201c\u7a7f\u900f\u201d\u3002<\/span><\/div>\n\n\n\n
\u51fd\u6570\u5b9a\u4e49\uff08\u5c01\u88c5\u53ef\u590d\u7528\u7684\u4ee3\u7801\uff09<\/h4>\n\n\n\n
int add(int ad,int ba){ \/\/ \u6709\u8fd4\u56de\u503c\uff1a\u8fd4\u56deint\u7c7b\u578b\uff0c\u53c2\u6570\u4e5f\u8981\u6307\u5b9a\u7c7b\u578b\n  return ad+ba;\n}\nvoid printInfo(String name,int age){ \/\/ \u65e0\u8fd4\u56de\u503c\uff1a\u7528void\n  print(\"\u59d3\u540d:$name,\u5e74\u9f84:$age\");\n}\ngetvalue(){ \/\/ \u7701\u7565\u8fd4\u56de\u503c\u7c7b\u578b\uff1aDart\u81ea\u52a8\u63a8\u65ad\uff08\u4e0d\u63a8\u8350\uff09\n  return \"123\";\n}<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\uff1a\u51fd\u6570\u662f \u201c\u80fd\u91cd\u590d\u8c03\u7528\u7684\u4ee3\u7801\u5757\u201d\uff0c\u6307\u5b9a\u53c2\u6570 \/ \u8fd4\u56de\u503c\u7c7b\u578b\u66f4\u89c4\u8303\u3002<\/span><\/div>\n\n\n\n
command<\/code> \u51fd\u6570\uff08\u53ef\u9009\u53c2\u6570\uff09<\/h4>\n\n\n\n
String command(String a,[String? b = \"12\",String? c]){\/\/\u53ef\u9009\u53c2\u6570\n  return a+ (b ?? \"\")+ (c ?? \"\");\n}<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\u7279\u70b9<\/strong>\uff1a\u53ef\u9009\u53c2\u6570\u7528 []<\/code> \u5305\u88f9\uff0c\u610f\u601d\u662f \u201c\u53ef\u4f20\u53ef\u4e0d\u4f20\u201d\u3002
a<\/code> \u662f\u5fc5\u9009\u53c2\u6570<\/strong>\uff1a\u8c03\u7528\u65f6\u5fc5\u987b\u4f20\u503c\uff08\u6bd4\u5982\u793a\u4f8b\u91cc\u7684 \"add\"<\/code>\uff09\uff1b
b<\/code> \u662f\u5e26\u9ed8\u8ba4\u503c\u7684\u53ef\u9009\u53c2\u6570<\/strong>\uff1a\u4e0d\u4f20\u7684\u8bdd\u9ed8\u8ba4\u7528 \"12\"<\/code>\uff0c\u4f20\u4e86\u5c31\u7528\u4f20\u7684\u503c\uff08\u793a\u4f8b\u91cc\u4f20\u4e86 \"1\"<\/code>\uff0c\u8986\u76d6\u9ed8\u8ba4\u503c\uff09\uff1b
c<\/code> \u662f\u65e0\u9ed8\u8ba4\u503c\u7684\u53ef\u9009\u53c2\u6570<\/strong>\uff1a\u4e0d\u4f20\u7684\u8bdd\u5c31\u662f null<\/code>\uff0c\u6240\u4ee5\u7528 ?? \"\"<\/code> \u5904\u7406\uff08\u7a7a\u503c\u5c31\u7528\u7a7a\u5b57\u7b26\u4e32\uff0c\u907f\u514d\u62fc\u63a5\u62a5\u9519\uff09\u3002

\u8c03\u7528\u6548\u679c<\/strong>\uff1acommand(\"add\",\"1\")<\/code> \u2192 \u62fc\u63a5 a(\"add\") + b(\"1\") + c(\"\")<\/code> \u2192 \u8fd4\u56de \"add1\"<\/code>\uff0c\u6253\u5370\u51fa\u6765\u3002<\/span><\/div>\n\n\n\n
showPerson<\/code> \u51fd\u6570\uff08\u547d\u540d\u53c2\u6570\uff09<\/h4>\n\n\n\n
showPerson(String name,{int? age,String? sex}){\/\/\u547d\u540d\u53c2\u6570\n  print(\"\u59d3\u540d:$name,\u5e74\u9f84:$age,\u6027\u522b:$sex\");\n}<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\u7279\u70b9<\/strong>\uff1a\u547d\u540d\u53c2\u6570\u7528 {}<\/code> \u5305\u88f9\uff0c\u8c03\u7528\u65f6\u5fc5\u987b\u5199\u53c2\u6570\u540d\uff08age: 10<\/code> \u800c\u4e0d\u662f\u76f4\u63a5\u5199 10<\/code>\uff09\uff0c\u597d\u5904\u662f\u53c2\u6570\u987a\u5e8f\u53ef\u4ee5\u968f\u4fbf\u6362\uff0c\u53ef\u8bfb\u6027\u66f4\u9ad8\u3002 
name<\/code> \u662f\u5fc5\u9009\u53c2\u6570\uff1a\u5fc5\u987b\u4f20\uff1b
age<\/code>\/sex<\/code> \u662f\u547d\u540d\u53c2\u6570\uff1a\u4f20\u7684\u65f6\u5019\u8981\u5199 age:<\/code>\/sex:<\/code>\u3002

\u8c03\u7528\u6548\u679c<\/strong>\uff1ashowPerson(\"\u5f20\u4e09\",age: 10,sex: \"\u7537\")<\/code> \u2192 \u6253\u5370 \"\u59d3\u540d:\u5f20\u4e09,\u5e74\u9f84:10,\u6027\u522b:\u7537\"<\/code>\u3002<\/span><\/div>\n\n\n\n
\u51fd\u6570\u4f5c\u4e3a\u53c2\u6570\u4f20\u9012\uff08text<\/code> \u53d8\u91cf + showInfo<\/code> \u51fd\u6570\uff09<\/h4>\n\n\n\n
\/\/ \u628a\u4e00\u4e2a\u65e0\u53c2\u51fd\u6570\u8d4b\u503c\u7ed9\u53d8\u91cftext\uff08\u51fd\u6570\u4e5f\u662f\u4e00\u79cd\u6570\u636e\u7c7b\u578b\uff09\nFunction text = (){\n  print(\"\u6211\u662ftext\u51fd\u6570\");\n};\n\n\/\/ \u63a5\u6536\u4e00\u4e2a\u51fd\u6570\u7c7b\u578b\u7684\u53c2\u6570f\uff0c\u7136\u540e\u6267\u884c\u8fd9\u4e2a\u51fd\u6570\nvoid showInfo(Function f){\n  f();\n}<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u6838\u5fc3\u7279\u70b9<\/strong>\uff1aDart \u91cc\u51fd\u6570\u53ef\u4ee5\u50cf\u6570\u5b57\u3001\u5b57\u7b26\u4e32\u4e00\u6837\uff0c\u8d4b\u503c\u7ed9\u53d8\u91cf\uff0c\u4e5f\u80fd\u5f53\u4f5c\u53c2\u6570\u4f20\u7ed9\u5176\u4ed6\u51fd\u6570\u3002 
text<\/code> \u662f\u4e00\u4e2a\u51fd\u6570\u53d8\u91cf\uff1a\u5b58\u4e86\u4e00\u4e2a \u201c\u6253\u5370\u6307\u5b9a\u6587\u5b57\u201d \u7684\u65e0\u53c2\u51fd\u6570\uff1b
showInfo<\/code> \u63a5\u6536\u51fd\u6570\u53c2\u6570\uff1a\u53c2\u6570 f<\/code> \u662f\u51fd\u6570\u7c7b\u578b\uff0c\u8c03\u7528 f()<\/code> \u5c31\u662f\u6267\u884c\u4f20\u8fdb\u6765\u7684\u51fd\u6570\u3002

\u8c03\u7528\u6548\u679c<\/strong>\uff1ashowInfo(text)<\/code> \u2192 \u628a text<\/code> \u8fd9\u4e2a\u51fd\u6570\u4f20\u7ed9 showInfo<\/code>\uff0c\u6267\u884c\u540e\u6253\u5370 \"\u6211\u662ftext\u51fd\u6570\"<\/code>\u3002<\/span><\/div>\n\n\n\n
add<\/code> \u51fd\u6570\uff08\u7bad\u5934\u51fd\u6570\uff09<\/h4>\n\n\n\n
int add(int a,int b)=>a+b;\/\/\u7bad\u5934\u51fd\u6570\uff0c\u8fd4\u56dea+b\n\n\/\/\u6838\u5fc3\u7279\u70b9<\/strong>\uff1a\u7bad\u5934\u51fd\u6570\u662f Dart \u5bf9 \u201c\u903b\u8f91\u7b80\u5355\u7684\u51fd\u6570\u201d \u7684\u7b80\u5316\u5199\u6cd5\uff0c\u76f8\u5f53\u4e8e\uff1a\nint add(int a,int b){\n  return a+b;\n}<\/code><\/pre>\n\n\n\n
<\/i><\/span>\u53ea\u6709\u4e00\u884c\u8fd4\u56de\u903b\u8f91\u65f6\uff0c\u7528 =><\/code> \u66ff\u4ee3 {}<\/code> \u548c return<\/code>\uff0c\u4ee3\u7801\u66f4\u7b80\u6d01\u3002
\u8c03\u7528\u6548\u679c<\/strong>\uff1aadd(1,2)<\/code> \u2192 \u8fd4\u56de 3<\/code>\uff0c\u6253\u5370\u51fa\u6765\u3002<\/span><\/div>\n\n\n\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
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