摸索数组中的相似记录一个键？
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【中文标题】摸索数组中的相似记录一个键？【英文标题】：Groping simillar records in an array a key? 【发布时间】：2020-12-10 06:06:06 【问题描述】：我下面有一个这样的数组
[
"Date": "2020-07",
"data": [
"id": "35ebd073-600c-4be4-a750-41c4be5ed24a",
"Date": "2020-07-03T00:00:00.000Z",
"transactionId": "13",
"transactionType": "Payment",
"amount": 1500
]
,
"Date": "2020-07",
"data": [
"id": "4e126519-e27b-4e82-bb81-689c7dc63c9b",
"Date": "2020-07-02T00:00:00.000Z",
"transactionId": "4",
"transactionType": "Payment",
"amount": 1000
]
,
"Date": "2020-06",
"data": [
"id": "646d6497-9dea-4f27-896e-a45d97a252ea",
"Date": "2020-06-04T00:00:00.000Z",
"transactionId": "14",
"transactionType": "Payment",
"amount": 1500
]
,
"Date": "2020-06",
"data": [
"id": "cf44e27f-2111-462d-b3bd-420a193745b8",
"Date": "2020-06-02T00:00:00.000Z",
"transactionId": "5",
"transactionType": "Payment",
"amount": 1000
]
]
这里有键Date，同一个日期键有两个值。现在我想如果日期相同，那么数据数组记录应该合并。
所以我希望输出为
[
"Date": "2020-07",
"data": [
"id": "35ebd073-600c-4be4-a750-41c4be5ed24a",
"Date": "2020-07-03T00:00:00.000Z",
"transactionId": "13",
"transactionType": "Payment",
"amount": 1500
,
"id": "4e126519-e27b-4e82-bb81-689c7dc63c9b",
"Date": "2020-07-02T00:00:00.000Z",
"transactionId": "4",
"transactionType": "Payment",
"amount": 1000
]
,
"Date": "2020-06",
"data": [
"id": "646d6497-9dea-4f27-896e-a45d97a252ea",
"Date": "2020-06-04T00:00:00.000Z",
"transactionId": "14",
"transactionType": "Payment",
"amount": 1500
,
"id": "cf44e27f-2111-462d-b3bd-420a193745b8",
"Date": "2020-06-02T00:00:00.000Z",
"transactionId": "5",
"transactionType": "Payment",
"amount": 1000
]
]
请告诉我最好的优化方式吗？
【问题讨论】：
这能回答你的问题吗？ Group object values by date 【参考方案1】：您可以使用dictionary 并轻松检查密钥是否已存在，然后追加新数据，否则您将添加日期作为新密钥。
var dict = ;
if (!("xxxx-xx" in dict)) //if the key is not the dict
dict["xxxx-xx"] = [ //we are storing an array because we want to add other later
id: "....",
transactionId: "..."
//etc...
]
else //if the key already exists, we push new data to the array
dict["xxxx-xx"].push( //you can use push because is an array of objects
id: "....",
transactionId: "..."
//etc...
)
我希望它会有所帮助。 array 不太方便检查键是否已经存在和避免重复（默认情况下使用dict/object）。
【讨论】：
请根据那个检查我想要的预期输出。 日期字段是多余的，当然如果你真的需要那个输出，这不是一个选择，但更适合你想做的事情。而不是“日期和数据”的对象，您只有一个标识他的数据的键 如果输出无法更改，这是一个有效的答案***.com/a/40775082/4757993【参考方案2】：arr = 你的数据集
obj = 这将是你的输出
arr.forEach((elem) =>
if(obj[elem.Date])
obj[elem.Date].data.push(elem.data);
else
obj[elem.Date] =
data: [elem.data]
);
【讨论】：
请根据此检查我想要的预期输出。【参考方案3】：首先，您必须按属性Date 对该对象数组进行分组。并迭代按[Date, groupsByDate] 的键值对分组，然后从每个组中获取数据
const res = _.chain(data)
.groupBy("Date")
.toPairs()
.map(([key, value]) => (
Date: key,
data: _.flatMap(value, "data"),
))
.value()
完整代码
const data = [
Date: "2020-07",
data: [
id: "35ebd073-600c-4be4-a750-41c4be5ed24a",
Date: "2020-07-03T00:00:00.000Z",
transactionId: "13",
transactionType: "Payment",
amount: 1500,
,
],
,
Date: "2020-07",
data: [
id: "4e126519-e27b-4e82-bb81-689c7dc63c9b",
Date: "2020-07-02T00:00:00.000Z",
transactionId: "4",
transactionType: "Payment",
amount: 1000,
,
],
,
Date: "2020-06",
data: [
id: "646d6497-9dea-4f27-896e-a45d97a252ea",
Date: "2020-06-04T00:00:00.000Z",
transactionId: "14",
transactionType: "Payment",
amount: 1500,
,
],
,
Date: "2020-06",
data: [
id: "cf44e27f-2111-462d-b3bd-420a193745b8",
Date: "2020-06-02T00:00:00.000Z",
transactionId: "5",
transactionType: "Payment",
amount: 1000,
,
],
,
]
const res = _.chain(data)
.groupBy("Date")
.toPairs()
.map(([key, value]) => (
Date: key,
data: _.flatMap(value, "data"),
))
.value()
console.log(JSON.stringify(res, null, 2))<script src="https://cdn.jsdelivr.net/npm/lodash@4.17.20/lodash.min.js"></script>【讨论】：
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