Question

我试图通过给出KEY来从KEY，VALUE对象中找到值。关键是数组。

var arr = ["1398","1392","1390"];
var objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };

我需要从键在数组中的对象中找到所有值。我怎样才能做到这一点？到目前为止，我做到了这一点：

for (var a=0; a<arr.length;a++) {
    console.log(arr[a]);
}

for (var k in objects){
    if (typeof objects[k] !== 'function') {
         console.log(k + ", " + objects[k]);
    }
}

Answer 1

您可以按objects[ arr[ 0 ] ]查找返回systemConfiguration

的值

0，1和2是arr的关键

你可以循环找到所有。喜欢：

var arr = ["1398", "1392", "1390"];
var objects = {
  1384: "registerItem",
  1386: "createGroups",
  1388: "vipNumbers",
  1390: "targetNumbers",
  1392: "ignoredNumbers",
  1394: "globalConstants",
  1396: "Users",
  1398: "systemConfiguration",
  1400: "applicationErrors"
};

for (var key in arr) {
  if( typeof objects[arr[key]] != 'undefined' ) console.log(objects[arr[key]]);
}

Answer 2

您可以使用underscore.js选择方法。

＆＃13;

var arr = ["1398","1392","1390"];
var objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };

console.log(_.pick(objects,arr))

//For Values
console.log(_.chain(objects).pick(arr).values().value());

＆＃13;

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

＆＃13;

Answer 3

你可以循环你的数组，然后检查当前索引是否在你的对象中：

＆＃13;

var objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };
var arr = ["1398","1392","1390"];
arr.forEach(function(entry) {
    if(entry in objects) console.log(objects[entry]);
});

＆＃13;

Answer 4

我该怎么做？

通过传递map函数来使用callback方法。

＆＃13;

var arr = ["1398", "1392", "1390"];
var objects = {
  1384: "registerItem",
  1386: "createGroups",
  1388: "vipNumbers",
  1390: "targetNumbers",
  1392: "ignoredNumbers",
  1394: "globalConstants",
  1396: "Users",
  1398: "systemConfiguration",
  1400: "applicationErrors"
};

console.log(arr.map(a => objects[a]));

＆＃13;

Answer 5

我需要找到键在数组中的对象的所有值。

在ES5环境中，我可能会使用forEach和push，使用in或hasOwnProperty进行检查（具体取决于您是否要查看原型）查看对象是否有密钥：

＆＃13;

var arr = ["1398","1392","1390"];
var objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };
var values = [];
arr.forEach(function(key) {
    if (key in objects) {
        values.push(objects[key]);
    }
});
console.log(values);

＆＃13;

在ES2015 +环境中，我可能会使用for-of代替forEach：

＆＃13;

const arr = ["1398","1392","1390"];
const objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };
const values = [];
for (const key of arr) {
    if (key in objects) {
        values.push(objects[key]);
    }
}
console.log(values);

＆＃13;

最后，如果已经知道该对象包含属性而根本不需要检查，则可以使用map：

＆＃13;

var arr = ["1398","1392","1390"];
var objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };
var values = arr.map(function(key) {
    return objects[key];
});
console.log(values);

＆＃13;

......在ES2015 +中可以使用简洁的箭头功能：

＆＃13;

const arr = ["1398","1392","1390"];
const objects = { 1384: "registerItem", 1386: "createGroups", 1388: "vipNumbers", 1390: "targetNumbers", 1392: "ignoredNumbers", 1394: "globalConstants", 1396: "Users", 1398: "systemConfiguration", 1400: "applicationErrors" };
const values = arr.map(key => objects[key]);
console.log(values);

＆＃13;

Answer 6

尝试减少数组，并创建一个新对象{}并为对象中存在的那些键取key,value对，或者创建一个新数组[]并保持推送对象中存在的那些键的值。取决于你的要求。

arr.reduce(function(init, key) {
    if(objects[key]) { init[key] = objects[key]; };
    return init;
}, {});

OR

arr.reduce(function(init, key) {
        if(objects[key]) { init.push(objects[key]); };
        return init;
}, []);

并使用underscore或lodash更好地从数组端进行迭代并将对象用作map，而不是从对象侧进行迭代，这里你去：

_(arr).map(k=>objects[k]).compact().value()

通过给出key，从key，val对象中查找值

6 个答案: