js对json数组的操作-查、删、改、增

1、json数组

var persons = [
    {name: "tina", age: 14},
    {name: "timo", age: 15},
    {name: "lily", age: 16},
    {name: "lucy", age: 16}
]

2、根据对象属性值得到相应对象

//1. 获取 name 等于 lily 的对象
var lily = persons.filter((p) => {
    return p.name == "lily";
});
console.log(lily); //打印结果 [{name: "lily", age: 16}]



//注：filter()方法返回的是一个数组
var twins = persons.filter((p) => {
    return p.age == 16;
});
console.log(twins); //打印结果 [{name: "lily", age: 16},{name: "lucy", age: 16}]

3、删除其中一个对象

//删除 name 等于 tina 的对象，利用splice()方法

//1. 首先我们要得到这个对象
var tina = persons.filter((p) => {
    return p.name == "tina";
});

//2. 其次得到这个对象在数组中对应的索引
var index = persons.indexOf(tina[0]);

//3. 如果存在则将其删除，index > -1 代表存在
index > -1 && persons.splice(index, 1);

console.log(persons);
//打印结果 [{name: "timo", age: 15}, {name: "lily", age: 16}, {name: "lucy", age: 16}]

4、修改其中一个对象的属性值

//将 name 等于 timo 的 age 修改为 20

//1. 得到 timo 对象
var timo = persons.filter((p) => {
    return p.name == "timo";
});

//2. 修改age
timo[0].age = 20;

5、数组中添加一个对象

persons.push({name: "similar", age: 18});

 

转载于:https://www.cnblogs.com/congfeicong/p/10382034.html