JSON 到 JavaScript 中的字典？
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JSON to dictionary in JavaScript?
提问by Vivek Ragunathan
In my JS code, I need to convert the JSON response from server to a dictionary so that I can access them by key names. Here is the situation:
在我的 JS 代码中，我需要将来自服务器的 JSON 响应转换为字典，以便我可以通过键名访问它们。这是情况：
Say, this is the JSON response from my server:
说，这是来自我的服务器的 JSON 响应：
{
'status': 'success',
'employees' : [
{ 'id': 12, 'name': 'Tom', 'department': 'finance' },
{ 'id': 34, 'name': 'Dick', 'department': 'admin' },
{ 'id': 56, 'name': 'Harry', 'department': 'marketing' }
]
}
Now what i need is to create a dictionary variable such that the key is the id and the value is the (say) name so that i can access them variable.id or variable[id_value] (from a loop).
现在我需要的是创建一个字典变量，键是 id，值是（比如）名称，以便我可以访问它们 variable.id 或 variable[id_value]（从循环中）。
How can this be achieved? Your help highly appreciated.
如何做到这一点？非常感谢您的帮助。
Thanks Vivek Ragunathan
感谢 Vivek Ragunathan
回答by nnnnnn
Note that that is not valid JSON: you have to use double-quotes, not single-quotes.
请注意，这不是有效的 JSON：您必须使用双引号，而不是单引号。
Assuming you fix that, and that the JSON has already been retrieved into a string variable jsonResult, you need to parse that to get an object using JSON.parse():
假设你解决了这个问题，并且 JSON 已经被检索到一个字符串变量中jsonResult，你需要解析它以使用JSON.parse()获取一个对象：
var result = JSON.parse(jsonResult);
You can build a dictionary from there:
您可以从那里构建字典：
var employees = {};
for (var i = 0, emp; i < result.employees.length; i++) {
emp = result.employees[i];
employees[ emp.id ] = emp;
}
console.log(employees[56].name); // logs "Harry"
console.log(employees[56].department); // logs "marketing"
You said "and the value is the (say) name" - if you don't need the departmentvalues then in the for loop above say employees[ emp.id ] = emp.name;and then (obviously) employees[56]would give you "Harry" directly.
您说“并且值是（说）名称”-如果您不需要这些department值，那么在上面的 for 循环中说employees[ emp.id ] = emp.name;然后（显然）employees[56]会直接给您“Harry”。
回答by Jonathan Lonowski
Well, assuming the JSON has already been parsed to an Object:
好吧，假设 JSON 已经被解析为一个Object：
var data = JSON.parse('{"status":"success","employees":[{},{},{}]}'); // abridged
You can loop over data.employeesto build the "dictionary" (Object):
您可以循环data.employees构建“字典”( Object)：
var employees = {};
for (var i = 0; i < data.employees.length; i++) {
employees[data.employees[i].id] = data.employees[i];
}
Then, given an employeeId:
然后，给定一个employeeId：
var employee = employees[employeeId];
回答by Darin Dimitrov
You could write a javascript function to get an employee by id from a list of employees:
您可以编写一个 javascript 函数来通过员工列表中的 id 获取员工：
function getEmployee(id, employees) {
for (var i = 0; i < employees.length; i++) {
var employee = employees[i];
if (employee.id === id) {
return employee;
}
}
return null;
}
and then use this function on the response you got from the server after parsing the JSON string back to a javascript object:
然后在将 JSON 字符串解析回 javascript 对象后，对从服务器获得的响应使用此函数：
var json = 'the JSON string you got from the server';
var obj = JSON.parse(json);
var employees = obj.employees;
var employee = getEmployee(34, employees);
if (employee != null) {
alert(employee.name);
}
回答by CRice
Something like this allows you to create a dictionary in one line, and specify the key and value used, or at least the key where the value becomes the entire object.
这样的东西允许你在一行中创建一个字典，并指定使用的键和值，或者至少是值成为整个对象的键。
function toDictionary(items, key, value) {
var dictionary = {};
if (items) {
for (var i = 0; i < items.length; i++) {
var item = items[i];
dictionary[key(item)] = value ? value(item) : item;
}
}
return dictionary;
}
Example usage:
用法示例：
var dictionary = toDictionary(result.employees, function (record) { return record.id; });
var employee = dictionary[34];
if (employee) {
// do something with employee object
}
