从名称为JSON的数组中获取一项 [英] get one item from an array of name,value JSON

问题描述

我有这个数组:

var arr = [];
arr.push({name:"k1", value:"abc"});
arr.push({name:"k2", value:"hi"});
arr.push({name:"k3", value:"oa"});

是否可以通过知道名称来获取值或特定元素?

is it possible to do get the value or a specific element by knowing the name ?

类似这样的东西:

arr['k2'].value

或

arr.get('k1')

推荐答案

通常通过数字索引访问数组，因此在您的示例arr[0] == {name:"k1", value:"abc"}中.如果您知道每个对象的name属性都是唯一的，则可以将它们存储在对象而不是数组中，如下所示:

Arrays are normally accessed via numeric indexes, so in your example arr[0] == {name:"k1", value:"abc"}. If you know that the name property of each object will be unique you can store them in an object instead of an array, as follows:

var obj = {};
obj["k1"] = "abc";
obj["k2"] = "hi";
obj["k3"] = "oa";

alert(obj["k2"]); // displays "hi"

如果您实际上想要一个像帖子中那样的对象数组，则可以遍历该数组并在找到具有具有所需属性的对象的元素时返回:

If you actually want an array of objects like in your post you can loop through the array and return when you find an element with an object having the property you want:

function findElement(arr, propName, propValue) {
  for (var i=0; i < arr.length; i++)
    if (arr[i][propName] == propValue)
      return arr[i];

  // will return undefined if not found; you could return a default instead
}

// Using the array from the question
var x = findElement(arr, "name", "k2"); // x is {"name":"k2", "value":"hi"}
alert(x["value"]); // displays "hi"

var y = findElement(arr, "name", "k9"); // y is undefined
alert(y["value"]); // error because y is undefined

alert(findElement(arr, "name", "k2")["value"]); // displays "hi";

alert(findElement(arr, "name", "zzz")["value"]); // gives an error because the function returned undefined which won't have a "value" property

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