鸿蒙学习笔记
第一节 数据类型
鸿蒙官方文档https://developer.harmonyos.com/cn/documentation/overview/
//TODO 数字
let number1 : number = 199
let number2 : number = 0b11 //2进制
let number3 : number = 0x99 //16进制
let number4 : number = 0o132 //8进制
number1.toFixed(0)//保留小数点几位并转为字符串
//TODO 字符串
let string1 : string = "zs"
let string2 : string = "zhu ye lin"
let string3 : string = `you name is ${string2}` //另外一种拼接方法
//TODO 联合类型
let objectType : string | number | boolean
objectType = true
objectType = "eqweqw"
objectType = 5234235
objectType = true
//TODO array
let strarr1 : string[] = ['1','2','3']
// enum Color {Rad,Green,Blue}
// let color : Color.Green
//TODO map
let name1 : [string,number]
name1 = ["李四",20]
//TODO Unknown未知类型 相当于java Object
let testType : unknown = 7
testType = 'qwezdf'
testType = true
//函数
function name(params) : number {
return 0;
}
//Null
let str1 : null = null
//undefined
let str2 : undefined = undefined
在if中空字符串,0,null,undefined都是false
for遍历
let names : string[] = ['jack','rose']
for(let i in names){
console.log(i+" : "+names[i])
}
for(let name of names){
console.log(name)
}
}