数组删除一项 / 对象删除一项

经常用到，记一笔

1、object

var jone={
    name:'Jone',
    age:"18",
    sex:"male",
    weight:'70kg'
};
var skills=['vue','react','angular','jquery','bootstrap'];

delete jone.sex;

//输出
//var jone={
    //name:'Jone',
    //age:"18",
    //weight:'70kg'
//};



delete skills[1];
//输出skills=['vue',empty,'angular','jquery','bootstrap'];
//其中empty的判断可以理解为undefined。

2、array

//删除首位
var skills=['vue','react','angular','jquery','bootstrap'];

skills.shift();//返回 "vue"

//打印skills,skills.length
//输出["react", "angular", "jquery", "bootstrap"],length=4;

skills.pop();//返回 "bootstrap"

//打印skills,skills.length
//输出["react", "angular", "jquery"],length=3;


//删除任意项

数组.splice(起始下标（必填）,要删除的元素个数（必填，0则不删）,"要从起始下标开始添加的元素（选填，可以同时加多个）")
//返回你选中要删除的数组元素，以数组格式返回；
//执行后数组直接更新


skills=['vue','react','angular','jquery','bootstrap'];

skills.splice(1,1)//返回["react"]


//打印skills,skills.length
//输出 ["vue", "angular", "jquery", "bootstrap"],length=4;

skills.splice(1,2,'1','2','3')//返回["angular", "jquery"]

//打印skills,skills.length
["vue", "1", "2", "3", "bootstrap"],length=5;

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