字典

简介

1 .以键值对存储数据的数据结构

class Dict{
    constructor(){
        this.dataStore=[]
        // 这里并不是用的object，而是用的array来存储
        this.dataLength=0
    }
    add(key,value){
        this.dataStore[key]=value
        this.dataLength++
        console.log(this.dataStore)
    }
    find(key){
        return this.dataStore[key]
    }
    remove(key){
        delete this.dataStore[key]
        this.dataLength--
    }
    showAll(){
        for(let key in this.dataStore){
            console.log(key,this.dataStore[key])
        }
    }
    count(){
        return this.dataLength
    }
    clear(){
        this.dataStore=[]
        this.dataLength=0
    }
}

var pbook = new Dict(); 
pbook.add("Mike","123");
pbook.add("David", "345");
pbook.add("Cynthia", "456");
pbook.showAll();
pbook.remove("Cynthia");
console.log(pbook.count());//2
pbook.clear();
console.log(pbook.count());//0