应用条件过滤器获取 JSON 数组的唯一值

Question

我有一个这样的 JSON 数组 ...

[
  {
    "Event_code": "AB-001",
    "Interest_area": "Arts and Education",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-002",
    "Interest_area": "Arts and Education",
    "Start_time": "12:30 PM",
    "End_time": "1:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-003",
    "Interest_area": "",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-004",
    "Interest_area": "Business",
    "Start_time": "10:30 AM",
    "End_time": "11:00 AM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-005",
    "Interest_area": "General Interest",
    "Start_time": "9:30 AM",
    "End_time": "1:30 PM",
    "Session_type": "Experience"
  },
  {
    "Event_code": "AB-006",
    "Interest_area": "Environment, Business",
    "Start_time": "11:00 AM",
    "End_time": "11:30 AM",
    "Session_type": "Course information session"
  },
 {
    "Event_code": "AB-014",
    "Interest_area": "Health sciences and allied health, Medicine",
    "Start_time": "1:00 PM",
    "End_time": "2:00 PM",
    "Session_type": "Course information session"
  }
    ]

我想要做的是过滤这个 JSON 并提取 unique "Interest_area" 值，其中 "Session_type" 等于 "课程说明会" ...

我的预期输出是

["艺术与教育","商业","环境"]

我已经看到this 解决方案，这与我正在寻找的非常接近，但它在我的情况下不起作用，因为我的 JSON 可能有“2 个或更多”值用于“兴趣区域”字段。

Answer 1

首先使用Array#filter() 过滤以获得非空兴趣和适当的会话类型

Array#reduce() 过滤结果到感兴趣的Set。一个 Set 只能有唯一值并忽略重复项

最后将Set转回数组

let interestSet = data       
  .filter(obj=> obj.Interest_area && obj.Session_type === "Course information session")   
  .reduce((a, c)=> a.add(...c.Interest_area.split(',')), new Set);
  
let uniques = [...interestSet];

console.log(uniques)

<script>
let data = [
  {
    "Event_code": "AB-001",
    "Interest_area": "Arts and Education",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-002",
    "Interest_area": "Arts and Education",
    "Start_time": "12:30 PM",
    "End_time": "1:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-003",
    "Interest_area": "",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-004",
    "Interest_area": "Business",
    "Start_time": "10:30 AM",
    "End_time": "11:00 AM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-005",
    "Interest_area": "General Interest",
    "Start_time": "9:30 AM",
    "End_time": "1:30 PM",
    "Session_type": "Experience"
  },
  {
    "Event_code": "AB-006",
    "Interest_area": "Environment,Business",
    "Start_time": "11:00 AM",
    "End_time": "11:30 AM",
    "Session_type": "Course information session"
  }
]
</script>

Answer 2

你可以这样做：

let result = [...new Set(                                              //Use new Set to get unique values
   arr.filter(o=>o.Session_type === search && o.Interest_area.trim() !== '' ) //Use filter to filter the Session_type and Interest_area is not blank
      .reduce((c,v)=>c.concat(v.Interest_area.split(',')),[]))         //Use reduce and concat to flatten the array
      .map(o=>o.trim())                                                //Use map to trim the values
]

这是一个sn-p：

let arr=[{"Event_code":"AB-001","Interest_area":"Arts and Education","Start_time":"9:00 AM","End_time":"3:00 PM","Session_type":"Course information session"},{"Event_code":"AB-002","Interest_area":"Arts and Education","Start_time":"12:30 PM","End_time":"1:00 PM","Session_type":"Course information session"},{"Event_code":"AB-003","Interest_area":"","Start_time":"9:00 AM","End_time":"3:00 PM","Session_type":"Course information session"},{"Event_code":"AB-004","Interest_area":"Business","Start_time":"10:30 AM","End_time":"11:00 AM","Session_type":"Course information session"},{"Event_code":"AB-005","Interest_area":"General Interest","Start_time":"9:30 AM","End_time":"1:30 PM","Session_type":"Experience"},{"Event_code":"AB-006","Interest_area":"Environment   ,    Business       ","Start_time":"11:00 AM","End_time":"11:30 AM","Session_type":"Course information session"}];

let search = 'Course information session';
let result = [...new Set(arr.filter(o=>o.Session_type === search && o.Interest_area.trim() !== '' ).reduce((c,v)=>c.concat(v.Interest_area.split(',')),[]).map(o=>o.trim()))]

console.log(result);

文档：new Set()、filter()、reduce()、concat()

Answer 3

你必须循环每个子数组并检查会话类型的值，然后提取兴趣区域

var obj = [
  {
    "Event_code": "AB-001",
    "Interest_area": "Arts and Education",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-002",
    "Interest_area": "Arts and Education",
    "Start_time": "12:30 PM",
    "End_time": "1:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-003",
    "Interest_area": "",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-004",
    "Interest_area": "Business",
    "Start_time": "10:30 AM",
    "End_time": "11:00 AM",
    "Session_type": "Course information session"
  },
  {
    "Event_code": "AB-005",
    "Interest_area": "General Interest",
    "Start_time": "9:30 AM",
    "End_time": "1:30 PM",
    "Session_type": "Experience"
  },
  {
    "Event_code": "AB-006",
    "Interest_area": "Environment,Business",
    "Start_time": "11:00 AM",
    "End_time": "11:30 AM",
    "Session_type": "Course information session"
  }
]

var interest_list = [];
$.each(obj, function(event,details){
  if(details['Session_type'] === 'Course information session'){
    var addnew = details['Interest_area'].split(",");
    interest_list.push(addnew);
  }
}

console.log(interest_list);