JS数组:标记重复项 [英] JS Array: tagging duplicates

问题描述

我有一个像这样的对象数组...

I have an array of objects like this ...

[{
    "Event_code": "AB-001",
    "Interest_area": "Arts",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
}, {
    "Event_code": "AB-002",
    "Interest_area": "Arts",
    "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": "9:00 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"
}]

我正在寻找一种针对开始时间"冲突的过滤器.我的预期输出应包含一个额外的键值对，例如"clash":"Yes".因此，预期输出应为..

I am looking to implement a filter for 'Start_time' clash. My expected output should contain an extra key value pair something like "clash": "Yes". So the expected output should be ..

[{
    "Event_code": "AB-001",
    "Interest_area": "Arts",
    "Start_time": "9:00 AM",
    "End_time": "3:00 PM",
    "Session_type": "Course information session"
}, {
    "Event_code": "AB-002",
    "Interest_area": "Arts",
    "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",
     "clash": "yes" // Newly added key/value
}, {
    "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": "9:00 AM",
    "End_time": "1:30 PM",
    "Session_type": "Experience",
     "clash": "yes" // Newly added key/value
}, {
    "Event_code": "AB-006",
    "Interest_area": "Environment ,    Business       ",
    "Start_time": "11:00 AM",
    "End_time": "11:30 AM",
    "Session_type": "Course information session"
}]

请注意，额外的键/值"对出现在第一次冲突(上午9:00)之后，而不是第一次出现.我已经在此处看到了类似的解决方案，但这并没有标记重复项，而是删除了重复项.

Notice the extra "key/value" pair appears on the 1st clash (9:00 AM) onwards, not on the initial occurrence. I have seen a similar solution here but this doesn't tag duplicates, it rather removes them.

非常感谢.

推荐答案

使用使用 if/else

var arr = [{"Event_code":"AB-001","Interest_area":"Arts","Start_time":"9:00 AM","End_time":"3:00 PM","Session_type":"Course information session"},{"Event_code":"AB-002","Interest_area":"Arts","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":"9:00 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 st = {};
arr.forEach(o => {
  if(st[o.Start_time]) o.clash = "yes";
  else st[o.Start_time] = o.Start_time;
});
console.log(arr);

使用三元运算符

var arr = [{"Event_code":"AB-001","Interest_area":"Arts","Start_time":"9:00 AM","End_time":"3:00 PM","Session_type":"Course information session"},{"Event_code":"AB-002","Interest_area":"Arts","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":"9:00 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 st = {};
arr.forEach(o => st[o.Start_time] ? o.clash = "yes": st[o.Start_time] = o.Start_time);
console.log(arr);

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