让你想更新数组[2]= "data"的值

    for(i=0;i<array.length;i++){
      if(i == 2){
         array[i] = "data";
        }
    }

你可以在你的例子中使用。find so

   var projects = [
            {
                value: "jquery",
                label: "jQuery",
                desc: "the write less, do more, JavaScript library",
                icon: "jquery_32x32.png"
            },
            {
                value: "jquery-ui",
                label: "jQuery UI",
                desc: "the official user interface library for jQuery",
                icon: "jqueryui_32x32.png"
            },
            {
                value: "sizzlejs",
                label: "Sizzle JS",
                desc: "a pure-JavaScript CSS selector engine",
                icon: "sizzlejs_32x32.png"
            }
        ];

let project = projects.find((p) => {
    return p.value === 'jquery-ui';
});

project.desc = 'your value'

这是我对这个问题的回应。我的下划线版本是1.7，因此我不能使用. findindex。

所以我手动获取了item的索引并替换了它。这里是相同的代码。

 var students = [ 
{id:1,fName:"Ajay", lName:"Singh", age:20, sex:"M" },
{id:2,fName:"Raj", lName:"Sharma", age:21, sex:"M" },
{id:3,fName:"Amar", lName:"Verma", age:22, sex:"M" },
{id:4,fName:"Shiv", lName:"Singh", age:22, sex:"M" }
               ]

下面的方法将用对象中更多的属性替换id:4的学生

function updateStudent(id) {
 var indexOfRequiredStudent = -1;
    _.each(students,function(student,index) {                    
      if(student.id === id) {                        
           indexOfRequiredStudent = index; return;      
      }});
 students[indexOfRequiredStudent] = _.extend(students[indexOfRequiredStudent],{class:"First Year",branch:"CSE"});           

}

使用下划线1.8，它将被简化，因为我们有方法_.findIndexOf。

let users = [
    {id: 1, name: 'Benedict'},
    {id: 2, name: 'Myles'},
    {id: 3, name: 'Happy'},
]

 users.map((user, index) => {
 if(user.id === 1){
  users[index] = {id: 1, name: 'Baba Benny'};    
 }
 
 return user
})


console.log(users)

这段代码所做的是映射对象，然后匹配所需的 使用if语句，

if(user.id === 1) 

一旦有匹配的地方使用它的索引交换

 users[index] = {id: 1, name: 'Baba Benny'};

对象，然后返回修改后的数组

最简单的方法就是这样做

    var projects = [
{
    
    
    value: "jquery",
    label: "jQuery",
    desc: "the write less, do more, JavaScript library",
    icon: "jquery_32x32.png"
},
{
    value: "jquery-ui",
    label: "jQuery UI",
    desc: "the official user interface library for jQuery",
    icon: "jqueryui_32x32.png"
}];

projects.find(data => data.value === "jquery").label ="xxxx"

console.log("------------>",projects)

你可以使用map函数——

const answers = this.state.answers.map(answer => {
  if(answer.id === id) return { id: id, value: e.target.value }
  return answer
})

this.setState({ answers: answers })