dart学习笔记

常用数据类型

定义数据类型的方式

vat str = 'this is str';

定义变量的指定类型：
String str = `this is str`
String str = '''this is str
	this is str
	this is str ''' //多行字符串变量赋值需要使用3个引号
           

String str1 = '你好' ;
String str2 = 'dart' ;
print ("$str1 $str2") ;
print (str1 + “ ” + str2) ;
           

int a = 123
double b =23.33
           

bool flag = true
bool flag = false
           

var li = ['aaa', 'bbb', 'ccc']
print(li.length) => 3
print(li[1]) => 'bbb'

定义指定list类型
var list = new List<String>();
list.add('张三');
           

var person = {
	"name": "张三",
	"age": 20
}

var p = new Map();
p["name"] = "李四";
p["age"] = 20
           

判断变量类型

if (str is String) {
	print('String类型');
}else {
	print('其他类型');
}