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通过给定键从key,val对象中查找值

javascript-objects arrays javascript

Bilal Zafar · 技术社区 · 8 年前

我试图通过给键,从对象的键,值对中找到值。钥匙在数组中。

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" };

我需要从键位于数组中的对象中查找所有值。我该怎么做? 到目前为止,我做到了:

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]);
    }
}

6 回复 | 直到 8 年前

Eddie 8 年前

您可以通过以下方式找到值: objects[ arr[ 0 ] ] 将返回 systemConfiguration

哪里 0 , 1 和 2 是 arr

您可以循环查找所有内容。例如:

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]]);
}

Kishore Kumar 8 年前

您可以使用 underscore.js 选取方法。

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());

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

Amani Ben Azzouz 8 年前

可以循环数组,然后检查当前索引是否在对象中:

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]);
});

Mihai Alexandru-Ionut 8 年前

我该怎么做?

只需使用 map 通过传递 callback 作用

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]));

T.J. Crowder 8 年前

我需要从键位于数组中的对象中查找所有值。

在ES5环境中,我可能会使用 forEach 和 push ,正在检查 in 或 hasOwnProperty (取决于您是否要检查原型)以查看对象是否具有键:

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);

在ES2015+环境中,我可能会使用 for-of 而不是 :

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);

最后,如果你 已经知道了 对象包含属性,完全不需要检查,您可以使用 map :

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);

...在ES2015+中,可以使用简明箭头功能:

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);

Koushik Chatterjee 8 年前

尝试减少数组,然后创建一个新对象 {} 然后拿着 key,value 为对象中存在的键配对,或创建新数组 []

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

或

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

和使用 underscore 或 lodash 最好从数组端进行迭代,并将对象用作映射,而不是从对象端进行迭代

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