{"id":186,"date":"2023-05-15T09:15:09","date_gmt":"2023-05-15T01:15:09","guid":{"rendered":"https:\/\/www.escook.cn\/?p=186"},"modified":"2023-09-26T21:09:12","modified_gmt":"2023-09-26T13:09:12","slug":"dart-%e5%9f%ba%e7%a1%80-%e5%86%85%e7%bd%ae%e7%b1%bb%e5%9e%8b-%e6%95%b0%e5%ad%97","status":"publish","type":"post","link":"https:\/\/www.escook.cn\/index.php\/2023\/05\/15\/dart-%e5%9f%ba%e7%a1%80-%e5%86%85%e7%bd%ae%e7%b1%bb%e5%9e%8b-%e6%95%b0%e5%ad%97\/","title":{"rendered":"Dart \u57fa\u7840 – \u5185\u7f6e\u7c7b\u578b – \u6570\u5b57"},"content":{"rendered":"
\n

\u7248\u6743\u5f52\u4f5c\u8005 \u00a9\u5218\u9f99\u5bbe<\/strong> \u6240\u6709\uff0c\u672c\u6587\u7ae0\u672a\u7ecf\u4f5c\u8005\u5141\u8bb8\uff0c\u7981\u6b62\u79c1\u81ea\u8f6c\u8f7d\uff01<\/p>\n<\/blockquote>\n

\u5728 Dart \u8bed\u8a00\u4e2d\uff0c\u63d0\u4f9b\u4e86 int<\/strong> \u548c double<\/strong> \u4e24\u79cd\u6570\u5b57\u7c7b\u578b\u3002\u5176\u4e2d int<\/code> \u7528\u6765\u8868\u793a\u6574\u6570\u6570\u5b57<\/strong>\uff0cdouble<\/code> \u7528\u6765\u8868\u793a\u5305\u542b\u5c0f\u6570\u70b9\u7684\u6570\u5b57<\/strong>\u3002\u5b83\u4eec\u90fd\u7ee7\u627f\u81ea num<\/code><\/strong> \u62bd\u8c61\u7c7b\uff0c\u5177\u4f53\u5173\u7cfb\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n

<\/p>\n

1. int \u548c double<\/h2>\n

\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\uff0c\u5982\u679c\u5e0c\u671b\u660e\u786e\u5b9a\u4e49\u4e0d\u5305\u542b\u5c0f\u6570\u4f4d<\/strong>\u7684\u6574\u6570\u6570\u5b57\uff0c\u53ef\u4ee5\u4f7f\u7528 int<\/code> \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n

void main(List<String> args) {\n  int age = 10;\n  print(age); \/\/ \u8f93\u51fa 10\n}<\/code><\/pre>\n
\u5982\u679c\u5e0c\u671b\u660e\u786e\u5b9a\u4e49\u5305\u542b\u5c0f\u6570\u4f4d<\/strong>\u7684\u6570\u5b57\uff0c\u53ef\u4ee5\u4f7f\u7528 double<\/code> \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  double price = 5.5;\n  print(price); \/\/ \u8f93\u51fa 5.5\n}<\/code><\/pre>\n
\u4ece Dart 2.1 \u5f00\u59cb\uff0c\u5fc5\u8981\u7684\u65f6\u5019 int \u5b57\u9762\u91cf\u4f1a\u81ea\u52a8\u8f6c\u6362<\/strong>\u6210 double<\/code> \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  \/\/ 1. \u628a int \u5b57\u9762\u91cf 10 \u8d4b\u503c\u7ed9 double \u7c7b\u578b\u7684\u53d8\u91cf price\n  double price = 10;\n  \/\/ 2. \u8f93\u51fa price \u7684\u503c\uff0c\u53d1\u73b0\u53d8\u6210\u4e86\u5305\u542b\u5c0f\u6570\u4f4d\u7684 double \u7c7b\u578b\u7684\u503c\uff1a10.0\n  print(price);\n}<\/code><\/pre>\n
2. \u7236\u7c7b\u578b num<\/h2>\n
\u5728\u5b9a\u4e49\u6570\u5b57\u7684\u65f6\u5019\uff0c\u65e0\u8bba\u662f int<\/code> \u8fd8\u662f double<\/code> \u7c7b\u578b\u7684\u6570\u5b57\uff0c\u90fd\u53ef\u4ee5\u4f7f\u7528\u7236\u7c7b\u578b num<\/code><\/strong> \u6765\u8868\u793a\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  \/\/ \u5b9a\u4e49 num \u7c7b\u578b\u7684\u53d8\u91cf a \u548c b\uff0c\u5176\u4e2d\uff1a\n  \/\/ \u4e3a\u53d8\u91cf a \u8d4b\u503c\u6574\u6570 10\n  num a = 10;\n  \/\/ \u4e3a\u53d8\u91cf b \u8d4b\u503c\u5e26\u5c0f\u6570\u7684\u6570\u5b57 1.1\n  num b = 1.1;\n}<\/code><\/pre>\n
\u56e0\u6b64\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\uff0c\u5982\u679c\u67d0\u4e2a\u6570\u5b57\u7684\u7c7b\u578b\u4e0d\u660e\u786e\uff0c\u63a8\u8350\u4f7f\u7528\u7236\u7c7b\u578b num<\/code> \u6765\u8868\u793a<\/strong>\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  \/\/ 1. \u5b9a\u4e49\u6570\u5b57\u7c7b\u578b\u7684\u53d8\u91cf price\uff0c\u5177\u4f53\u662f\u5c0f\u6570\u8fd8\u662f\u6574\u6570\u4e0d\u660e\u786e\n  num price;\n\n  \/\/ 2. \u4e3a price \u8d4b\u503c\u4e3a\u6574\u6570 10\n  price = 10;\n  print(price); \/\/ \u8f93\u51fa 10\n\n  \/\/ 3. \u4e3a price \u8d4b\u503c\u4e3a\u5e26\u5c0f\u6570\u7684\u6570\u5b57 1.1\n  price = 1.1;\n  print(price); \/\/ \u8f93\u51fa 1.1\n}<\/code><\/pre>\n
3. int \u4e0e double \u8fdb\u884c\u8fd0\u7b97<\/h2>\n
int<\/code> \u7c7b\u578b\u7684\u5b57\u9762\u91cf\u4e0e double<\/code> \u7c7b\u578b\u7684\u5b57\u9762\u91cf\u8fdb\u884c\u8fd0\u7b97\uff0c\u6700\u7ec8\u5f97\u5230\u7684\u7ed3\u679c\u4e3a double<\/code> \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  num result = 10 + 1.1;\n  print(result); \/\/ \u8f93\u51fa 11.1\n\n  \/\/ \u6ce8\u610f\uff1aDart \u4e2d\u7684 is \u662f\u7c7b\u578b\u5224\u65ad\u64cd\u4f5c\u7b26\uff0c\u7528\u6765\u5224\u65ad\u5de6\u4fa7\u7684\u6570\u636e\u662f\u5426\u4e3a\u53f3\u4fa7\u7684\u7c7b\u578b\uff0c\u8bed\u6cd5\u5982\u4e0b\uff1a\n  \/\/ \u6570\u636e is \u7c7b\u578b\n  \/\/ \u5982\u679c\u8fd4\u56de true\uff0c\u5219\u8868\u793a\u5de6\u4fa7\u6570\u636e\u662f\u53f3\u4fa7\u7c7b\u578b\uff1b\u5982\u679c\u8fd4\u56de false\uff0c\u5219\u8868\u793a\u5de6\u4fa7\u6570\u636e\u4e0d\u662f\u53f3\u4fa7\u7c7b\u578b\u3002\n  print(result is int); \/\/ \u8f93\u51fa false\uff0c\u8868\u793a\u8fd0\u7b97\u7684\u7ed3\u679c\u4e0d\u662f int \u7c7b\u578b\n  print(result is double); \/\/ \u8f93\u51fa true\uff0c\u8868\u793a\u8fd0\u7b97\u7684\u7ed3\u679c\u662f double \u7c7b\u578b\n}<\/code><\/pre>\n
4. \u5b57\u7b26\u4e32\u8f6c\u6570\u5b57<\/h2>\n
\u5982\u679c\u5e0c\u671b\u628a\u5b57\u7b26\u4e32\u8f6c\u6362\u4e3a\u6570\u5b57<\/strong>\uff0c\u53ef\u4ee5\u8c03\u7528 int<\/code>\u3001double<\/code>\u3001num<\/code> \u7684\u7c7b\u63d0\u4f9b\u7684\u9759\u6001\u65b9\u6cd5 parse(\u5b57\u7b26\u4e32)<\/code>\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  int a = int.parse('10');\n  print(a); \/\/ \u8f93\u51fa 10\n\n  double b = double.parse('1.1');\n  print(b); \/\/ \u8f93\u51fa 1.1\n\n  num c = num.parse('20');\n  print(c); \/\/ \u8f93\u51fa 20\n  print(c is int); \/\/ \u8f93\u51fa true\n\n  num d = num.parse('2.2');\n  print(d); \/\/ \u8f93\u51fa 2.2\n  print(d is double); \/\/ \u8f93\u51fa true\n}<\/code><\/pre>\n
\u5728\u8c03\u7528 parse()<\/code> \u628a\u5b57\u7b26\u4e32\u8f6c\u4e3a\u6570\u5b57\u7684\u8fc7\u7a0b\u4e2d\uff0c\u53ef\u80fd\u4f1a\u51fa\u73b0\u8f6c\u6362\u5931\u8d25\u5bfc\u81f4\u7a0b\u5e8f\u8fd0\u884c\u5f02\u5e38<\/strong>\u7684\u95ee\u9898\u3002\u4e3a\u4e86\u9632\u6b62\u5f02\u5e38\u62a5\u9519\uff0c\u53ef\u4ee5\u4f7f\u7528 tryParse()<\/code> \u9759\u6001\u65b9\u6cd5\u8fdb\u884c\u8f6c\u6362\u3002\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  \/\/ 1. \u5982\u679c\u8f6c\u6362\u6210\u529f\uff0c\u5219\u8f6c\u6362\u7684\u7ed3\u679c\u662f\u9884\u671f\u7684\u6570\u5b57\n  int? a = int.tryParse('10');\n  print(a); \/\/ \u8f93\u51fa 10\n\n  \/\/ 2. \u5982\u679c\u8f6c\u6362\u5931\u8d25\uff0c\u5219\u8f6c\u6362\u7684\u7ed3\u679c\u662f null\uff0c\u4ece\u800c\u9632\u6b62\u7a0b\u5e8f\u8fd0\u884c\u5f02\u5e38\u7684\u95ee\u9898\n  \/\/ \u6ce8\u610f\uff1a\u8fd9\u91cc\u7684 int? \u8868\u793a"\u53ef\u7a7a int \u7c7b\u578b"\uff1a\u8868\u793a\u53d8\u91cf\u7684\u503c\u65e2\u53ef\u4ee5\u662f int \u6574\u6570\uff0c\u4e5f\u53ef\u4ee5\u662f null\n  int? b = int.tryParse('10\u5168\u5927\u8865\u6c64');\n  print(b); \/\/ \u8f93\u51fa null\n}<\/code><\/pre>\n
\u6ce8\u610f\uff1aint.parse()<\/code> \u53ea\u80fd\u8f6c\u6362 int \u6574\u6570\uff0c\u5728\u4f7f\u7528 int.parse()<\/code> \u8f6c\u6362\u5e26\u5c0f\u6570\u70b9\u7684\u6570\u5b57\u65f6\u4f1a\u62a5\u9519\uff0c\u4f8b\u5982\u4e0b\u9762\u7684\u4ee3\u7801\u5728\u8fd0\u884c\u65f6\u4f1a\u4ea7\u751f\u5f02\u5e38<\/strong>\uff1a<\/p>\n
void main(List<String> args) {\n  \/\/ Unhandled exception:\n  \/\/ FormatException: Invalid radix-10 number (at character 1)\n  \/\/ 1.1\n  \/\/ ^\n  int c = int.parse('1.1');\n  print(c);\n}<\/code><\/pre>\n
\u56e0\u6b64\uff0c\u5982\u679c\u4e0d\u786e\u5b9a\u8981\u8f6c\u7684\u7ed3\u679c\u4e2d\u662f\u5426\u5305\u542b\u5c0f\u6570<\/strong>\uff0c\u5efa\u8bae\u8c03\u7528 num.parse()<\/code> \u8fdb\u884c\u8f6c\u6362\u3002\u5982\u679c\u5305\u542b\u5c0f\u6570<\/strong>\uff0c\u5219\u8f6c\u6362\u7684\u7ed3\u679c\u662f double<\/code> \u7c7b\u578b\uff1b\u5982\u679c\u4e0d\u5305\u542b\u5c0f\u6570<\/strong>\uff0c\u5219\u8f6c\u6362\u7684\u7ed3\u679c\u662f int<\/code>\u7c7b\u578b\u3002\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  num a = num.parse('10');\n  print(a); \/\/ \u8f93\u51fa 10\n  print(a is int); \/\/ \u8f93\u51fa true\n\n  num b = num.parse('1.1');\n  print(b); \/\/ \u8f93\u51fa 1.1\n  print(b is double); \/\/ \u8f93\u51fa true\n}<\/code><\/pre>\n
5. \u6570\u5b57\u8f6c\u5b57\u7b26\u4e32<\/h2>\n
\u5982\u679c\u5e0c\u671b\u628a\u6570\u5b57\u8f6c\u4e3a\u5b57\u7b26\u4e32\uff0c\u53ef\u4ee5\u8c03\u7528 toString()<\/code> \u51fd\u6570\uff0c\u8fd8\u53ef\u4ee5\u8c03\u7528 toStringAsFixed(n)<\/code> \u6307\u5b9a\u4fdd\u7559\u591a\u5c11\u4f4d\u5c0f\u6570\u3002\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a<\/p>\n
void main(List<String> args) {\n  int a = 10;\n  print(a.toString()); \/\/ \u8f93\u51fa\u5b57\u7b26\u4e32 10\n  \/\/ toStringAsFixed(n) \u51fd\u6570\u7528\u6765\u6307\u5b9a\u5c0f\u6570\u70b9\u540e\u4fdd\u7559\u591a\u5c11\u4f4d\u5c0f\u6570\uff0cn \u662f\u6570\u5b57\n  print(a.toStringAsFixed(2)); \/\/ \u8f6c\u4e3a\u5b57\u7b26\u4e32\u5e76\u4fdd\u7559\u4e24\u4f4d\u5c0f\u6570\uff0c\u8f93\u51fa\u5b57\u7b26\u4e32 10.00\n\n  double b = 1.1;\n  print(b.toString()); \/\/ \u8f93\u51fa 1.1\n  print(b.toStringAsFixed(2)); \/\/ \u8f6c\u4e3a\u5b57\u7b26\u4e32\u5e76\u4fdd\u7559\u4e24\u4f4d\u5c0f\u6570\uff0c\u8f93\u51fa\u5b57\u7b26\u4e32 1.10\n\n  num c = 4.567;\n  num d = 1.234;\n  \/\/ toStringAsFixed() \u5728\u4fdd\u7559\u5c0f\u6570\u65f6\uff0c\u4f1a\u8fdb\u884c\u56db\u820d\u4e94\u5165\n  print(c.toStringAsFixed(1)); \/\/ \u8f6c\u4e3a\u5b57\u7b26\u4e32\u5e76\u4fdd\u7559\u4e00\u4f4d\u5c0f\u6570\uff0c\u8f93\u51fa\u5b57\u7b26\u4e32 4.6\n  print(d.toStringAsFixed(1)); \/\/ \u8f6c\u4e3a\u5b57\u7b26\u4e32\u5e76\u4fdd\u7559\u4e00\u4f4d\u5c0f\u6570\uff0c\u8f93\u51fa\u5b57\u7b26\u4e32 1.2\n}<\/code><\/pre>\n
6. \u5176\u5b83\u5e38\u7528\u51fd\u6570<\/h2>\n
    \n
  1. abs()<\/code> \u6c42\u7edd\u5bf9\u503c<\/li>\n
  2. ceil()<\/code> \u4e0a\u53d6\u6574<\/li>\n
  3. floor()<\/code> \u4e0b\u53d6\u6574<\/li>\n
  4. round()<\/code> \u56db\u820d\u4e94\u5165<\/li>\n
  5. toInt()<\/code> \u628a\u6570\u5b57\u8f6c\u4e3a int \u7c7b\u578b<\/li>\n
  6. toDouble()<\/code> \u628a\u6570\u5b57\u8f6c\u4e3a double \u7c7b\u578b<\/li>\n<\/ol>\n
    void main(List<String> args) {\n  \/\/ abs() \u6c42\u7edd\u5bf9\u503c\n  int a = -10;\n  print(a.abs()); \/\/ \u8f93\u51fa 10\n\n  \/\/ ceil() \u4e0a\u53d6\u6574\n  double b = 10.2;\n  print(b.ceil()); \/\/ \u8f93\u51fa 11\n\n  \/\/ floor() \u4e0b\u53d6\u6574\n  double c = 10.99;\n  print(c.floor()); \/\/ \u8f93\u51fa 10\n\n  \/\/ round() \u56db\u820d\u4e94\u5165\n  double d = 8.4;\n  double e = 8.5;\n  print(d.round()); \/\/ \u8f93\u51fa 8\n  print(e.round()); \/\/ \u8f93\u51fa 9\n\n  \/\/ toInt() \u628a\u6570\u5b57\u8f6c\u4e3a int \u7c7b\u578b\n  \/\/ \u6ce8\u610f\uff1a\u76f4\u63a5\u53bb\u6389\u5c0f\u6570\u4f4d\uff0c\u4e0d\u4f1a\u8fdb\u884c\u56db\u820d\u4e94\u5165\n  double f = 3.14;\n  double g = 7.98;\n  print(f.toInt()); \/\/ \u8f93\u51fa 3\n  print(g.toInt()); \/\/ \u8f93\u51fa 7\n\n  \/\/ toDouble() \u628a\u6570\u5b57\u8f6c\u4e3a double \u7c7b\u578b\n  int h = 3;\n  print(h.toDouble()); \/\/ \u8f93\u51fa 3.0\n}<\/code><\/pre>\n
    \n
    \u7248\u6743\u5f52\u4f5c\u8005 \u00a9\u5218\u9f99\u5bbe<\/strong> \u6240\u6709\uff0c\u672c\u6587\u7ae0\u672a\u7ecf\u4f5c\u8005\u5141\u8bb8\uff0c\u7981\u6b62\u79c1\u81ea\u8f6c\u8f7d\uff01<\/p>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"
    \u7248\u6743\u5f52\u4f5c\u8005 \u00a9\u5218\u9f99\u5bbe \u6240\u6709\uff0c\u672c\u6587\u7ae0\u672a\u7ecf\u4f5c\u8005\u5141\u8bb8\uff0c\u7981\u6b62\u79c1\u81ea\u8f6c\u8f7d\uff01 \u5728 Dart \u8bed\u8a00\u4e2d\uff0c\u63d0\u4f9b\u4e86 int \u548c double \u4e24\u79cd\u6570\u5b57\u7c7b\u578b\u3002\u5176\u4e2d int \u7528\u6765\u8868\u793a\u6574\u6570\u6570\u5b57\uff0cdouble \u7528\u6765\u8868\u793a\u5305\u542b\u5c0f\u6570\u70b9\u7684\u6570\u5b57\u3002\u5b83\u4eec\u90fd\u7ee7\u627f\u81ea num \u62bd\u8c61\u7c7b\uff0c\u5177\u4f53\u5173\u7cfb\u5982\u4e0b\u56fe\u6240\u793a\uff1a 1. int \u548c double \u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\uff0c\u5982\u679c\u5e0c\u671b\u660e\u786e\u5b9a\u4e49\u4e0d\u5305\u542b\u5c0f\u6570\u4f4d\u7684\u6574\u6570\u6570\u5b57\uff0c\u53ef\u4ee5\u4f7f\u7528 int \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { int age = 10; print(age); \/\/ \u8f93\u51fa 10 } \u5982\u679c\u5e0c\u671b\u660e\u786e\u5b9a\u4e49\u5305\u542b\u5c0f\u6570\u4f4d\u7684\u6570\u5b57\uff0c\u53ef\u4ee5\u4f7f\u7528 double \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { double price = 5.5; print(price); \/\/ \u8f93\u51fa 5.5 } \u4ece Dart 2.1 \u5f00\u59cb\uff0c\u5fc5\u8981\u7684\u65f6\u5019 int \u5b57\u9762\u91cf\u4f1a\u81ea\u52a8\u8f6c\u6362\u6210 double \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { \/\/ 1. \u628a int \u5b57\u9762\u91cf 10 \u8d4b\u503c\u7ed9 double \u7c7b\u578b\u7684\u53d8\u91cf price double price = 10; \/\/ 2. \u8f93\u51fa price \u7684\u503c\uff0c\u53d1\u73b0\u53d8\u6210\u4e86\u5305\u542b\u5c0f\u6570\u4f4d\u7684 double \u7c7b\u578b\u7684\u503c\uff1a10.0 print(price); } 2. \u7236\u7c7b\u578b num \u5728\u5b9a\u4e49\u6570\u5b57\u7684\u65f6\u5019\uff0c\u65e0\u8bba\u662f int \u8fd8\u662f double \u7c7b\u578b\u7684\u6570\u5b57\uff0c\u90fd\u53ef\u4ee5\u4f7f\u7528\u7236\u7c7b\u578b num \u6765\u8868\u793a\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { \/\/ \u5b9a\u4e49 num \u7c7b\u578b\u7684\u53d8\u91cf a \u548c b\uff0c\u5176\u4e2d\uff1a \/\/ \u4e3a\u53d8\u91cf a \u8d4b\u503c\u6574\u6570 10 num a = 10; \/\/ \u4e3a\u53d8\u91cf b \u8d4b\u503c\u5e26\u5c0f\u6570\u7684\u6570\u5b57 1.1 num b = 1.1; } \u56e0\u6b64\u5728\u5b9e\u9645\u5f00\u53d1\u4e2d\uff0c\u5982\u679c\u67d0\u4e2a\u6570\u5b57\u7684\u7c7b\u578b\u4e0d\u660e\u786e\uff0c\u63a8\u8350\u4f7f\u7528\u7236\u7c7b\u578b num \u6765\u8868\u793a\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { \/\/ 1. \u5b9a\u4e49\u6570\u5b57\u7c7b\u578b\u7684\u53d8\u91cf price\uff0c\u5177\u4f53\u662f\u5c0f\u6570\u8fd8\u662f\u6574\u6570\u4e0d\u660e\u786e num price; \/\/ 2. \u4e3a price \u8d4b\u503c\u4e3a\u6574\u6570 10 price = 10; print(price); \/\/ \u8f93\u51fa 10 \/\/ 3. \u4e3a price \u8d4b\u503c\u4e3a\u5e26\u5c0f\u6570\u7684\u6570\u5b57 1.1 price = 1.1; print(price); \/\/ \u8f93\u51fa 1.1 } 3. int \u4e0e double \u8fdb\u884c\u8fd0\u7b97 int \u7c7b\u578b\u7684\u5b57\u9762\u91cf\u4e0e double \u7c7b\u578b\u7684\u5b57\u9762\u91cf\u8fdb\u884c\u8fd0\u7b97\uff0c\u6700\u7ec8\u5f97\u5230\u7684\u7ed3\u679c\u4e3a double \u7c7b\u578b\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { num result = 10 + 1.1; print(result); \/\/ \u8f93\u51fa 11.1 \/\/ \u6ce8\u610f\uff1aDart \u4e2d\u7684 is \u662f\u7c7b\u578b\u5224\u65ad\u64cd\u4f5c\u7b26\uff0c\u7528\u6765\u5224\u65ad\u5de6\u4fa7\u7684\u6570\u636e\u662f\u5426\u4e3a\u53f3\u4fa7\u7684\u7c7b\u578b\uff0c\u8bed\u6cd5\u5982\u4e0b\uff1a \/\/ \u6570\u636e is \u7c7b\u578b \/\/ \u5982\u679c\u8fd4\u56de true\uff0c\u5219\u8868\u793a\u5de6\u4fa7\u6570\u636e\u662f\u53f3\u4fa7\u7c7b\u578b\uff1b\u5982\u679c\u8fd4\u56de false\uff0c\u5219\u8868\u793a\u5de6\u4fa7\u6570\u636e\u4e0d\u662f\u53f3\u4fa7\u7c7b\u578b\u3002 print(result is int); \/\/ \u8f93\u51fa false\uff0c\u8868\u793a\u8fd0\u7b97\u7684\u7ed3\u679c\u4e0d\u662f int \u7c7b\u578b print(result is double); \/\/ \u8f93\u51fa true\uff0c\u8868\u793a\u8fd0\u7b97\u7684\u7ed3\u679c\u662f double \u7c7b\u578b } 4. \u5b57\u7b26\u4e32\u8f6c\u6570\u5b57 \u5982\u679c\u5e0c\u671b\u628a\u5b57\u7b26\u4e32\u8f6c\u6362\u4e3a\u6570\u5b57\uff0c\u53ef\u4ee5\u8c03\u7528 int\u3001double\u3001num \u7684\u7c7b\u63d0\u4f9b\u7684\u9759\u6001\u65b9\u6cd5 parse(\u5b57\u7b26\u4e32)\uff0c\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { int a = int.parse('10'); print(a); \/\/ \u8f93\u51fa 10 double b = double.parse('1.1'); print(b); \/\/ \u8f93\u51fa 1.1 num c = num.parse('20'); print(c); \/\/ \u8f93\u51fa 20 print(c is int); \/\/ \u8f93\u51fa true num d = num.parse('2.2'); print(d); \/\/ \u8f93\u51fa 2.2 print(d is double); \/\/ \u8f93\u51fa true } \u5728\u8c03\u7528 parse() \u628a\u5b57\u7b26\u4e32\u8f6c\u4e3a\u6570\u5b57\u7684\u8fc7\u7a0b\u4e2d\uff0c\u53ef\u80fd\u4f1a\u51fa\u73b0\u8f6c\u6362\u5931\u8d25\u5bfc\u81f4\u7a0b\u5e8f\u8fd0\u884c\u5f02\u5e38\u7684\u95ee\u9898\u3002\u4e3a\u4e86\u9632\u6b62\u5f02\u5e38\u62a5\u9519\uff0c\u53ef\u4ee5\u4f7f\u7528 tryParse() \u9759\u6001\u65b9\u6cd5\u8fdb\u884c\u8f6c\u6362\u3002\u793a\u4f8b\u4ee3\u7801\u5982\u4e0b\uff1a void main(List<String> args) { \/\/ 1. \u5982\u679c\u8f6c\u6362\u6210\u529f\uff0c\u5219\u8f6c\u6362\u7684\u7ed3\u679c\u662f\u9884\u671f\u7684\u6570\u5b57 int? a = int…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[9],"class_list":["post-186","post","type-post","status-publish","format-standard","hentry","category-dart","tag-dart"],"_links":{"self":[{"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/posts\/186","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/comments?post=186"}],"version-history":[{"count":2,"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/posts\/186\/revisions"}],"predecessor-version":[{"id":581,"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/posts\/186\/revisions\/581"}],"wp:attachment":[{"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/media?parent=186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/categories?post=186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.escook.cn\/index.php\/wp-json\/wp\/v2\/tags?post=186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}