如何在 es6 中仅比较和过滤两个对象数组中不匹配的数组
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【中文标题】如何在 es6 中仅比较和过滤两个对象数组中不匹配的数组【英文标题】:How to compare and filter only unmatched arrays from two array of objects in es6 【发布时间】:2020-04-24 23:55:02 【问题描述】:在我的 Angular 应用程序中,我试图仅获取从 UI 修改的更新数组。
在这里,我有两个数组,其中一个角色名称已更改。我想比较并过滤掉修改过的对象,只返回那些修改过的数组。 (在这种情况下,role_name 值被修改)
我尝试在 ES6 的帮助下进行过滤,但它不起作用。
有人可以帮我解决我在哪里失踪吗?
var arr1 = [
"num" : null,
"role_name" : "ABC",
"profile" : "ff",
"user" : "1234",
"rn" : "1",
"user_name" : "Rywan"
,
"num" : null,
"role_name" : "DEF",
"profile" : "ff",
"user" : "1234",
"rn" : "2",
"user_name" : "adecg"
,
"num" : null,
"role_name" : "GHJ",
"profile" : "ff",
"user" : "1234",
"rn" : "3",
"user_name" : "dde"
,
"num" : null,
"role_name" : "RRT",
"profile" : "ff",
"user" : "1234",
"rn" : "4",
"user_name" : "kumar"
,
"num" : null,
"role_name" : "SFR",
"profile" : "ff",
"user" : "1234",
"rn" : "5",
"user_name" : "SASI"
];
var arr2 = [
"num" : null,
"role_name" : "ABC",
"profile" : "ff",
"user" : "1234",
"rn" : "1",
"user_name" : "Rywan"
,
"num" : null,
"role_name" : "ROLE_CHANGED",
"profile" : "ff",
"user" : "1234",
"rn" : "2",
"user_name" : "adecg"
,
"num" : null,
"role_name" : "GHJ",
"profile" : "ff",
"user" : "1234",
"rn" : "3",
"user_name" : "dde"
,
"num" : null,
"role_name" : "RRT",
"profile" : "ff",
"user" : "1234",
"rn" : "4",
"user_name" : "kumar"
,
"num" : null,
"role_name" : "SFR",
"profile" : "ff",
"user" : "1234",
"rn" : "5",
"user_name" : "SASI"
];
let filteredData;
filteredData = arr1.filter(function(o1)
//filter out (!) items in arr2
return arr2.some(function(o2)
return o1.role_name !== o2.role_name;
);
);
console.log(filteredData);
输出应该是
[
"num" : null,
"role_name" : "ROLE_CHANGED",
"profile" : "ff",
"user" : "1234",
"rn" : "2",
"user_name" : "adecg"
]
【问题讨论】:
如果预计两个数组中元素的顺序相同,则可以执行以下操作:const filteredData = arr2.filter((item, index) => item.role_name !== arr1[index].role_name);
你可以使用下划线库***.com/questions/28632281/…
【参考方案1】:
我们已有的解决方案有点不同。
在Object.keys()
使用filter()
时,如果值已更改为arr1[index].role_name !== arr2[index].role_name
,我们还可以根据数组的索引比较role_name
属性。这将返回我们已更改值的数组的所有索引。然后使用map()
根据找到的数组键为这些元素生成一个新数组。
所以解决办法是:
Object.keys(arr1).filter(index => arr1[index].role_name !== arr2[index].role_name)
.map(index => arr2[index]);
Object.keys()
:
Object.keys() 方法返回一个给定对象自己的可枚举属性名称的数组,其顺序与我们在正常循环中得到的顺序相同。
Array.prototype.filter()
:
filter() 方法创建一个新数组,其中包含通过所提供函数实现的测试的所有元素。
Array.prototype.map()
:
map() 方法创建一个新数组,其中填充了对调用数组中的每个元素调用提供的函数的结果。
我认为您可以尝试以下方法:
const arr1 = [
"num" : null,
"role_name" : "ABC",
"profile" : "ff",
"user" : "1234",
"rn" : "1",
"user_name" : "Rywan"
,
"num" : null,
"role_name" : "DEF",
"profile" : "ff",
"user" : "1234",
"rn" : "2",
"user_name" : "adecg"
,
"num" : null,
"role_name" : "GHJ",
"profile" : "ff",
"user" : "1234",
"rn" : "3",
"user_name" : "dde"
,
"num" : null,
"role_name" : "RRT",
"profile" : "ff",
"user" : "1234",
"rn" : "4",
"user_name" : "kumar"
,
"num" : null,
"role_name" : "SFR",
"profile" : "ff",
"user" : "1234",
"rn" : "5",
"user_name" : "SASI"
];
const arr2 = [
"num" : null,
"role_name" : "ABC",
"profile" : "ff",
"user" : "1234",
"rn" : "1",
"user_name" : "Rywan"
,
"num" : null,
"role_name" : "ROLE_CHANGED",
"profile" : "ff",
"user" : "1234",
"rn" : "2",
"user_name" : "adecg"
,
"num" : null,
"role_name" : "GHJ",
"profile" : "ff",
"user" : "1234",
"rn" : "3",
"user_name" : "dde"
,
"num" : null,
"role_name" : "RRT",
"profile" : "ff",
"user" : "1234",
"rn" : "4",
"user_name" : "kumar"
,
"num" : null,
"role_name" : "SFR",
"profile" : "ff",
"user" : "1234",
"rn" : "5",
"user_name" : "SASI"
];
const changedObjects = Object.keys(arr1).filter(index => arr1[index].role_name !== arr2[index].role_name)
.map(index => arr2[index]);
console.log(changedObjects);
希望对你有帮助!
【讨论】:
【参考方案2】:您的逻辑有点缺陷,因为您的 .some()
将始终返回 true,因为总有一个元素会有所不同。您要做的是实际检查任何一个角色名称是否相同。如果没有找到匹配项(即.some()
返回 false),那么您就知道 role_name 已更改:
const filteredData = arr2.filter((o1, i) =>
return !arr1.some((o2) =>
return o1.role_name === o2.role_name;
);
);
var arr1 = [
"num": null,
"role_name": "ABC",
"profile": "ff",
"user": "1234",
"rn": "1",
"user_name": "Rywan"
,
"num": null,
"role_name": "DEF",
"profile": "ff",
"user": "1234",
"rn": "2",
"user_name": "adecg"
,
"num": null,
"role_name": "GHJ",
"profile": "ff",
"user": "1234",
"rn": "3",
"user_name": "dde"
,
"num": null,
"role_name": "RRT",
"profile": "ff",
"user": "1234",
"rn": "4",
"user_name": "kumar"
,
"num": null,
"role_name": "SFR",
"profile": "ff",
"user": "1234",
"rn": "5",
"user_name": "SASI"
];
var arr2 = [
"num": null,
"role_name": "ABC",
"profile": "ff",
"user": "1234",
"rn": "1",
"user_name": "Rywan"
,
"num": null,
"role_name": "ROLE_CHANGED",
"profile": "ff",
"user": "1234",
"rn": "2",
"user_name": "adecg"
,
"num": null,
"role_name": "GHJ",
"profile": "ff",
"user": "1234",
"rn": "3",
"user_name": "dde"
,
"num": null,
"role_name": "RRT",
"profile": "ff",
"user": "1234",
"rn": "4",
"user_name": "kumar"
,
"num": null,
"role_name": "SFR",
"profile": "ff",
"user": "1234",
"rn": "5",
"user_name": "SASI"
];
const filteredData = arr2.filter((o1, i) =>
return !arr1.some((o2) =>
return o1.role_name === o2.role_name;
);
);
console.log(filteredData);
【讨论】:
太棒了!我的逻辑是问题以上是关于如何在 es6 中仅比较和过滤两个对象数组中不匹配的数组的主要内容,如果未能解决你的问题,请参考以下文章