从对象数组中的对象中检索数据

Question

我有一个像这样的对象列表。

我现在卡住了，无法弄清楚如何通过提交密钥来检索对象的值

"ListOfObjects": [
    {
        "SomethingToRetrieve": "This Is The First Value"
    },
    {
        "AnotherThingToRetrieve": "This Is Another Value "
    },
    {
        "LastToRetrieve": "This Is the Last Value"
    }
]

我想通过创建一个函数：

retrieveValue(Key){
    // by giving as Example AnotherThingToRetrieve
    // It will return the Value of this key 
    //return "This Is Another Value "
}

Answer 1

在你的 json 上使用forEach 。 Object.keys(e)将为您提供对象文字中的keys 。

1. 循环JSON
2. 循环遍历Object literal {}所有keys
3. 如果匹配，则与key返回value匹配。

 var ListOfObjects= [{"SomethingToRetrieve": "This Is The First Value"},{"AnotherThingToRetrieve": "This Is Another Value "},{ "LastToRetrieve": "This Is the Last Value"}] function getVal(key){ ListOfObjects.forEach(function(e){//step #1 Object.keys(e).forEach(function(eachKey){//step #2 if(key == eachKey){//step #3 console.log(e[key]); return ; } }) }) // one liner using find alert(Object.values(ListOfObjects.find(el=>Object.keys(el).find(ee=>ee==key)))) } getVal('AnotherThingToRetrieve');

您还可以使用find的find()方法返回first element in the provided array中满足提供的测试功能的first element in the provided array的值。警报下的注释语句。

Answer 2

您可以过滤所有具有该键的对象，然后从第一个匹配对象返回值。 如果最后省略[0] ，您将获得所有匹配值的数组。

 var listOfObjects = [ { "SomethingToRetrieve": "This Is The First Value" }, { "AnotherThingToRetrieve": "This Is Another Value " }, { "LastToRetrieve": "This Is the Last Value" } ] const retrieveValue = key => listOfObjects.filter(x => x[key]).map(x => x[key])[0]; console.log(retrieveValue("AnotherThingToRetrieve"))

Answer 3

您有一个嵌套数组。 您可以运行嵌套的for循环来遍历它，直到找到这样的匹配项：

 var listOfObjects = [ { "SomethingToRetrieve": "This Is The First Value" }, { "AnotherThingToRetrieve": "This Is Another Value " }, { "LastToRetrieve": "This Is the Last Value" } ] var key = "LastToRetrieve"; console.log(retrieveValue(key)); function retrieveValue(Key){ // by giving as Example AnotherThingToRetrieve // It will return the Value of this key //return "This Is Another Value " var value = ""; for(var obj in listOfObjects) { for(var item in listOfObjects[obj]) { if(item === key) { value = listOfObjects[obj][item]; break; } } } return value; }