Dart 的数据类型
- 1. 字符串类型
-
- 2. 集合类型
- 3. Maps（字典）
- 4. 类型判断
1. 字符串类型
void main() {
String str = '''this is str
this is str
this is str
this is str''';
print(str);
}
void main() {
String str = """this is str
this is str
this is str
this is str""";
print(str);
}
1.1 字符串拼接
void main() {
String str1 = 'Hello';
String str2 = 'Dart';
print('$str1 $str2');
}
void main() {
String str1 = 'Hello';
String str2 = 'Dart';
print(str1 + str2);
}
2. 集合类型
void main() {
var l1 = ["张三", 20, true];
print(l1);
print(l1.length);
print(l1[1]);
}
// 定义 List，指定类型
void main() {
var l2 = ["张三", "李四"];
print(l2);
}
void main() {
var l = [];
print(l);
print(l.length);
l.add("zhangsan");
l.add("李四");
l.add(20);
print(l);
print(l.length);
}
// 创建一个固定长度的集合
void main() {
var l = List.filled(2, "");
print(l);
l[0] = "张三";
l[1] = "李四";
print(l);
}
3. Maps（字典）
void main() {
var person = {
"name": "张三",
"age": 20,
"work": ["程序员", "外卖员"]
};
print(person);
print(person["name"]);
print(person['work']);
}
void main() {
var p = new Map();
p["name"] = "李四";
p["age"] = 22;
p["work"] = ["程序员", "外卖员"];
print(p);
}
4. 类型判断
void main() {
var str = '1234';
if (str is String) {
print('是string类型');
} else if (str is int) {
print('是int类型');
} else {
print('其他类型');
}
}
