javascript lodash/下划线；比较两个对象并删除重复项
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lodash/underscore; compare two objects and remove duplicates
提问by numediaweb
As you can see in the image below, I have some returned json datawith three objects; each contains a clients id => data.
如下图所示，我返回data了一些包含三个对象的json ；每个都包含一个客户 ID => 数据。
exact_match : {104}
match_4 : {104, 103}
match_2 : {104, 103, 68}
How can I "trim" or remove the duplicate objects based on previous ones? something like:
如何根据以前的对象“修剪”或删除重复的对象？就像是：
exact_match : {104}
match_4 : {103}
match_2 : {68}
I tried _.differencebut did not work (Maybe because it is for arrays not objects?):
我试过_.difference但没有用（也许是因为它是用于数组而不是对象？）：
var exact_match = data.exact_match,
match_four_digits = _.difference(data.match_4, data.exact_match),
match_two_digits = _.difference(data.match_2, data.exact_match, data.match_4),
Any help would be appreciated :)
任何帮助，将不胜感激 ：）
Update
更新
I need that the returned value has the same object data instead of a new array :)
我需要返回的值具有相同的对象数据而不是新数组:)
采纳答案by numediaweb
Thanks guys for the answers, I really appreciate your time.
谢谢大家的回答，我真的很感谢你的时间。
I searched further and found this postby Lodash developer that helped me came up with this snippet;
我进一步搜索，发现Lodash 开发人员的这篇文章帮助我想出了这个片段；
var data = {
exact_match: {
104: {
supplier_id: 104
}
},
match_four_digits: {
104: {
supplier_id: 104
},
68: {
supplier_id: 68
}
},
match_two_digits: {
104: {
supplier_id: 104
},
68: {
supplier_id: 68
},
103: {
supplier_id: 103
},
999: {
supplier_id: 999
}
}
};
var arr_match_four_digits = _.difference(_.keys(data.match_four_digits), _.keys(data.exact_match));
var arr_match_two_digits = _.difference(_.keys(data.match_two_digits), _.keys(data.match_four_digits), _.keys(data.exact_match));
$('#output1').html(JSON.stringify(data));
$('#output2').html(JSON.stringify(_.pick(data.match_four_digits, arr_match_four_digits)));
$('#output3').html(JSON.stringify(_.pick(data.match_two_digits, arr_match_two_digits)));<script src="https://cdn.rawgit.com/lodash/lodash/3.3.1/lodash.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
data
<pre><code><div id="output1"></div></code></pre>
arr_match_four_digits
<pre><code><div id="output2"></div></code></pre>
match_two_digits
<pre><code><div id="output3"></div></code></pre>回答by Jonathan Allard
It looks like you want to diff keys (or rather, it'd be efficient to — _.keys)
看起来你想要区分键（或者更确切地说，它会很有效 - _.keys）
_.difference(
_.keys({104: 1, 102: 3, 101: 0}), // ["104", "102", "101"]
_.keys({104: 1, 102: 3}) // ["104", "102"]
)
// [ "101" ]
Or, you could always convert your object to an array of pairs if you want to compare within the objects too (_.pairs):
或者，如果您也想在对象内进行比较，则始终可以将对象转换为成对数组 ( _.pairs)：
_.difference(
_.pairs({104: 1, 102: 3, 101: 0}), // [["104",1], ["102",3], ["101",0]]
_.pairs({104: 1, 102: 2}) // [["104",1], ["102",2]]
)
// [["102", 3], ["101", 0]]
回答by KhalilRavanna
I would create a map called unique, e.g. var unique = {};and then iterate over each key in your data and check if it's in unique. If it is in unique, delete the entry associated with that key, thus removing duplicates.
我会创建一个名为unique, eg的地图，var unique = {};然后遍历数据中的每个键并检查它是否在unique. 如果它在 中unique，则删除与该键关联的条目，从而删除重复项。
You could pull this check out as an alreadyFoundmethod:
你可以把这个检查作为一种alreadyFound方法：
var alreadyFound = function (key) {
if (!(key in unique)) {
unique[key] = true;
return false;
}
return true;
};
Then iterate over your data and check alreadyFound(key)for keyin your data, and delete the key if alreadyFound(key)returns true.
然后循环在你的数据，并检查alreadyFound(key)了key您的数据，并删除如果键alreadyFound(key)的回报true。
You could go messing with lodash/underscore methods but those might be inefficient depending on how you use them (and how they're implemented) and this should operate in linear time.
您可以使用 lodash/underscore 方法，但这些方法可能效率低下，具体取决于您如何使用它们（以及它们的实现方式），并且这应该在线性时间内运行。
It looks like for your specific use case the full solution would be something like:
对于您的特定用例，完整的解决方案看起来像：
var unique = {};
// Assume I copy and pasted alreadyFound here
var alreadyFound = ...;
for (var object in data) {
// Iterate through ids in each object in data
for (var id in object) {
// Remove this entry if it's already found
if (alreadyFound(id)) {
delete object[id];
}
}
}
