本文介绍了将平面对象数组转换为嵌套的对象数组的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
原始JSON数据（平台）：
Original JSON data (flat table):
[
{"id":"1","first_name":"Jason","last_name":"Martin","start_date":"1996-07-25","end_date":"2006-07-25","salary":"1234.56","city":"Toronto","description":"Programmer","department":"Finance","active":"1"},
{"id":"2","first_name":"Alison","last_name":"Mathews","start_date":"1976-03-21","end_date":"1986-02-21","salary":"6661.78","city":"Vancouver","description":"Tester","department":"Finance","active":"1"},
{"id":"3","first_name":"James","last_name":"Smith","start_date":"1978-12-12","end_date":"1990-03-15","salary":"6544.78","city":"Vancouver","description":"Tester","department":"QA","active":"1"},
{"id":"4","first_name":"Celia","last_name":"Rice","start_date":"1982-10-24","end_date":"1999-04-21","salary":"2344.78","city":"Vancouver","description":"Manager","department":"HR","active":"1"},
{"id":"5","first_name":"Robert","last_name":"Black","start_date":"1984-01-15","end_date":"1998-08-08","salary":"2334.78","city":"Vancouver","description":"Tester","department":"IT","active":"1"},
{"id":"6","first_name":"Linda","last_name":"Green","start_date":"1987-07-30","end_date":"1996-01-04","salary":"4322.78","city":"New York","description":"Tester","department":"QA","active":"1"},
{"id":"7","first_name":"David","last_name":"Larry","start_date":"1990-12-31","end_date":"1998-02-12","salary":"7897.78","city":"New York","description":"Manager","department":"HR","active":"1"}
]
我需要调用这样的函数：
I need to call the function like this:
nest(data,["city","description","department"])
第一个参数是整个数据集，第二个是定义嵌套级别的列数组。
The first parameter is the entire dataset, the second is an array of columns which define the nesting level.
预期的JSON输出：
[
{key: "city", value: "Toronto", count: 1, children:
[
{key: "description", value: "Programmer", count: 1, children:
[
{key: "department", value: "Finance", count: 1}
]
}
]
},
{key: "city", value: "Vancouver", count: 2, children:
[
{key: "description", value: "Tester", count: 3, children:
[
{key: "department", value: "Finance", count: 1},
{key: "department", value: "QA", count: 1},
{key: "department", value: "IT", count: 1}
]
},
{key: "description", value: "Manager", count: 1}
]
},
{key: "city", value: "New York", count: 2, children:
[
{key: "description", value: "Tester", count: 1, children:
[
{key: "department", value: "QA", count: 1}
]
},
{key: "description", value: "Manager", count: 1, children:
[
{key: "department", value: "HR", count: 1}
]
}
]
}
]
我尝试过编写一些递归函数，但是当我必须动态时我会一直卡住搜索树以避免重复。
I've tried writing a few recursive functions but keep getting stuck when I have to dynamically search the tree to avoid duplication.
推荐答案
认为这是一个有趣的小问题，所以我做到了......但是，我同意那些问你到目前为止尝试了什么的人。通常，您应该讨论特定的问题。
Thought this was a fun little question, so I did it... but, I do agree with the people who asked "what have you tried so far". Typically, you should talk about a specific problem.
// Groups a flat array into a tree.
// "data" is the flat array.
// "keys" is an array of properties to group on.
function groupBy(data, keys) {
if (keys.length == 0) return data;
// The current key to perform the grouping on:
var key = keys[0];
// Loop through the data and construct buckets for
// all of the unique keys:
var groups = {};
for (var i = 0; i < data.length; i++)
{
var row = data[i];
var groupValue = row[key];
if (groups[groupValue] == undefined)
{
groups[groupValue] = new Array();
}
groups[groupValue].push(row);
}
// Remove the first element from the groups array:
keys.reverse();
keys.pop()
keys.reverse();
// If there are no more keys left, we're done:
if (keys.length == 0) return groups;
// Otherwise, handle further groupings:
for (var group in groups)
{
groups[group] = groupBy(groups[group], keys.slice());
}
return groups;
}
调用这样的方法：
var groupedData = groupBy(data, ["city","description","department"]);
此方法对您的数据的输出如下所示：
The output from this method for your data looks like this:
{
"Toronto": {
"Programmer": {
"Finance": [
{
"id": "1", "first_name": "Jason", "last_name": "Martin", "start_date": "1996-07-25", "end_date": "2006-07-25", "salary": "1234.56", "city": "Toronto", "description": "Programmer", "department": "Finance", "active": "1"
}
]
}
},
"Vancouver": {
"Tester": {
"Finance": [
{
"id": "2", "first_name": "Alison", "last_name": "Mathews", "start_date": "1976-03-21", "end_date": "1986-02-21", "salary": "6661.78", "city": "Vancouver", "description": "Tester", "department": "Finance", "active": "1"
}
],
"QA": [
{
"id": "3", "first_name": "James", "last_name": "Smith", "start_date": "1978-12-12", "end_date": "1990-03-15", "salary": "6544.78", "city": "Vancouver", "description": "Tester", "department": "QA", "active": "1"
}
],
"IT": [
{
"id": "5", "first_name": "Robert", "last_name": "Black", "start_date": "1984-01-15", "end_date": "1998-08-08", "salary": "2334.78", "city": "Vancouver", "description": "Tester", "department": "IT", "active": "1"
}
]
},
"Manager": {
"HR": [
{
"id": "4", "first_name": "Celia", "last_name": "Rice", "start_date": "1982-10-24", "end_date": "1999-04-21", "salary": "2344.78", "city": "Vancouver", "description": "Manager", "department": "HR", "active": "1"
}
]
}
},
"New York": {
"Tester": {
"QA": [
{
"id": "6", "first_name": "Linda", "last_name": "Green", "start_date": "1987-07-30", "end_date": "1996-01-04", "salary": "4322.78", "city": "New York", "description": "Tester", "department": "QA", "active": "1"
}
]
},
"Manager": {
"HR": [
{
"id": "7", "first_name": "David", "last_name": "Larry", "start_date": "1990-12-31", "end_date": "1998-02-12", "salary": "7897.78", "city": "New York", "description": "Manager", "department": "HR", "active": "1"
}
]
}
}
}
因为这些组都是javascript对象，所以您不需要count成员。您可以简单地使用数组的.length属性。
Because the groups are all javascript objects, you don't need that "count" member. You can simply use the .length property of the array(s).
使用javascript的循环组（组中的var组）语法。
Loop through the groups using javascript's for (var group in groups) syntax.
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