javascript 如何从打字稿数组中删除重复项？
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How to remove duplicates from a typescript array?
提问by user2753523
Could you let me know how do I remove duplicates from an Array in type script.
你能告诉我如何从类型脚本中的数组中删除重复项吗？
My array will look something like
我的阵列看起来像
a = [{a: 1, b: 2}, {a: 1, b: 2}, {c: 3, d: 4}]
I am looking to get
我正在寻找
a = [{a: 1, b: 2}, {c: 3, d: 4}]
I used Set data strucure like below
我使用了如下设置数据结构
a = Array.from(new Set(a))
but still no use. Please let me know how to remove duplicates from an array using single statement?
但还是没有用。请让我知道如何使用单个语句从数组中删除重复项？
回答by Ciro Spaciari
Is not in a single statement but is short.
不是在一个单一的声明中，而是简短的。
var a = [{a: 1, b: 2}, {a: 1, b: 2}, {c: 3, d: 4}];
a = a.filter((value, index, array) =>
!array.filter((v, i) => JSON.stringify(value) == JSON.stringify(v) && i < index).length);
console.log(a);Delete duplicated elements in array of objects Javascript
But like in the comment will fails for:
但就像在评论中会失败：
var a = [{a: 1, b: 2}, {b: 2, a: 1}];
You need a custom compare for your case:
您需要为您的案例进行自定义比较：
function isEqual(a, b){
for(var i in a)
if(a[i] != b[i])
return false;
for(var i in b)
if(b[i] != a[i])
return false;
return true;
}
var a = [{a: 1, b: 2}, {b: 2, a: 1}, {c: 3, d: 4}];
a = a.filter((value, index, array) =>
!array.filter((v, i) => isEqual(value, v) && i < index).length);
console.log(a);You can compare ids or somenthing like this to identify equal object in this sample i just compare the properties.
您可以比较 ids 或类似的东西来识别此示例中的相同对象，我只是比较属性。
Like @Juan Mendes said in comment:
就像@Juan Mendes 在评论中所说：
The reason your code doesn't filter elements is because two similar objects are still considered different objects because they point to different objects. You need to write your own code that uses a custom comparator.
您的代码不过滤元素的原因是两个相似的对象仍然被视为不同的对象，因为它们指向不同的对象。您需要编写自己的使用自定义比较器的代码。
