'buit_in_types'

Author: coderZoe

start/main.dart renamed to 0_start/main.dart

@@ -0,0 +1,6 @@
+import 'dart:html';
+
+void main() {
+  var request = HttpRequest();
+  request.setRequestHeader("content-type", "application/json");
+}

1_basic/libraries.dart

@@ -1,4 +1,4 @@
-import '../start/main.dart';
+import '../0_start/main.dart';
 
 void main() {
   var person1 = Person("Tom", 12);

basic/metadata.dart renamed to 1_basic/metadata.dart

@@ -0,0 +1,61 @@
+void main() {
+  int a = -10;
+  a = a.abs();
+  print(a);
+
+  double b = 123.5;
+  var c = b.floor();
+  print(c);
+  //num类型是int和double的合集类型
+  num d = 123.4;
+  d = d.floor();
+  print(d);
+
+  //字符串转数字
+  int number1 = int.parse('1');
+  assert(number1 == 1);
+  double number2 = double.parse("1.1");
+  assert(number2 == 1.1);
+
+  var number3 = num.parse('1.234');
+  assert(number3 == 1.234);
+
+  //数字转字符串
+  int number4 = 10;
+  var str1 = number4.toString();
+  assert(str1 == '10');
+
+  double pi = 3.1415926;
+  var str2 = pi.toStringAsFixed(2);
+  assert(str2 == '3.14');
+
+  var name = "小明";
+  Map xiaoming = {
+    'name': '小明',
+    'age': 12,
+    'hobbies': ['play', 'eat', 'sleep']
+  };
+  String str3 = 'Hello$name your age is ${xiaoming['age']}';
+  print(str3);
+
+  //字符串拼接
+  var str4 = str3 + str2;
+
+  //多行字符串
+  var str5 = '''
+name: my_project
+description: A new Dart project.
+version: 1.0.0
+
+environment:
+  sdk: '>=2.10.0 <3.0.0'
+
+dependencies:
+  http: ^0.13.3
+  ''';
+  print(str5);
+
+//原始字符串 不转义 使用r开头 加一段字符串
+  var str6 = r'In a raw string, not even \n gets special treatment.';
+  print(str6);
+}