如何在javascript中用数组对象值替换/更改数组值答案

【问题标题】：How to replace/change the array value with arrayobject value in javascript如何在javascript中用数组对象值替换/更改数组值
【发布时间】：2021-09-29 09:48:39
【问题描述】：

如何在javascript中通过数组值改变嵌套数组对象。

我有数组对象nestobj和数组arr，如果位置和数组匹配，则替换javascript中的值。

我需要知道如何用相同的变量名更改数组对象nestobj

var nestobj =[
  {id:1, name: "xyz", place: "CH"},
  {id:2, name: "zen", place: "JP"},
  {id:3, name: "abc", place: "TH"},
  {id:4, name: "ram", place: "MY"},
  {id:5, name: "mike", place: "AU"},
]


var arr=[
  "JP:Japan",
  "CH:Chennai",
  "AU:Australia"
]


Expected Ouput
[
  {id:1, name: "xyz", place: "Chennai"},
  {id:2, name: "zen", place: "Japan"},
  {id:3, name: "abc", place: "TH"},
  {id:4, name: "ram", place: "MY"},
  {id:5, name: "mike", place: "Australia"},
]

arr.map(ii=>{
  var kv = ii.split(':');
  nestobj.map(e=>{
    if(e.place === kv[0]){
   return { 
 ...e,
 place: kv[1]
    }
else{
   ...e,
  place: e.place
  }
   }
  })

})

console.log(nestobj)

【问题讨论】：

The map() method creates a new array populated with the results of calling a provided function on every element in the calling array。这意味着您需要 arr = arr.map(... 和/或 nestobj = nestobj.map(... 因为 map 不会替换其迭代的数组上的值。

标签： javascript arrays loops object

【解决方案1】：

我的方式...

const nestobj = 
  [ { id: 1, name: 'xyz',  place: 'CH' } 
  , { id: 2, name: 'zen',  place: 'JP' } 
  , { id: 3, name: 'abc',  place: 'TH' } 
  , { id: 4, name: 'ram',  place: 'MY' } 
  , { id: 5, name: 'mike', place: 'AU' } 
  ] 

const arr = [ 'JP:Japan', 'CH:Chennai', 'AU:Australia' ] 

const country =  Object.fromEntries(arr.map(e=>e.split(':')))

nestobj.forEach((e,i,a)=> { a[i].place =  country[e.place] ?? e.place })

console.log( nestobj )

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【讨论】：

【解决方案2】：

这是你的意思吗？

let nestobj =[
    {id:1, name: "xyz", place: "CH"},
    {id:2, name: "zen", place: "JP"},
    {id:3, name: "abc", place: "TH"},
    {id:4, name: "ram", place: "MY"},
    {id:5, name: "mike", place: "AU"},
  ]

  const arr=[
    "JP:Japan",
    "CH:Chennai",
    "AU:Australia",
  ]

  nestobj = nestobj.map((item, index) => {
    for(let i = 0; i < arr.length; i++) {
      const key = arr[i].split(":")[0]
      const value = arr[i].split(":")[1]

      if(item["place"] === key) {
        item["place"] = value
      }
    }
    return item
  })
  
  console.log(nestobj)

新的nestobj 将是：

[
  {id:1, name: "xyz", place: "Chennai"},
  {id:2, name: "zen", place: "Japan"},
  {id:3, name: "abc", place: "TH"},
  {id:4, name: "ram", place: "MY"},
  {id:5, name: "mike", place: "Australia"},
]

我建议你使用let（用于动态变量）和const（用于静态变量）来避免在Javascript中使用hoisting。

【讨论】：