如何使用纯Javascript从JSON数据中删除对象重复项，并按JSON对象中的日期信息对其进行排序

时间：2015-08-28 15:46:52

标签： javascript json

我试图接受一个JSON对象，遍历它，删除重复和冗余数据并按日期顺序输出（日期戳记在JSON对象中）。

具体清单如下：

  1. 输入数据将按日期顺序
  2. 应该首选来自最新日期的数据
  3. 重复ID计为重复项。重复的电子邮件计为重复。两者在数据集中必须是唯一的。其他地方的重复值不算作重复值。
  4. 如果日期相同，则应优先选择列表中最后提供的记录中的数据

    5. 这必须在纯JavaScript中完成。这是我到目前为止的代码：

    public class Message
{
   public static readonly int SizeInBytes = Marshal.SizeOf(typeof(this_type));
}

    我能够通过console.log（）看到对象，但每当我尝试操作它们时，我一直看到输出时出现错误和未定义。我不清楚这样做的确切机制。

    非常感谢，我在我的智慧结束。

    好的，为了扩展这个，我在JSFIDDLE上设置了一个帐户 Second one

1 个答案:

答案 0 :(得分：1)

我已经分享了你的jsfiddle：http://jsfiddle.net/limowankenobi/pak34wrz/

它仍然需要更多的工作，因为我只是删除重复项而不考虑日期。您应该能够根据您的要求对其进行修改以使用日期。

我创建了两个小函数：

第一个按照数组元素的属性（参数data）对数组（参数column）进行分组。

结果将是一个对象（地图），其属性（键）是所选列的唯一值，每个值都是具有该键的记录列表。

function groupBy(column, data) {
  var groups = {};

  data.forEach(function (itm) {
    groups[itm[column]] = groups[itm[column]] || [];
    groups[itm[column]].push(itm);
  });

  return groups;
}

第二个功能是展平列表地图。它需要一个对象迭代对象的每个属性（键）并选择一个元素。在这种情况下，我选择第一个元素，但我相信你应该修改它以根据日期选择元素。

function uniquify(groups) {
  var unique = [];
  for (var key in groups) {
    if (groups.hasOwnProperty(key)) {
      unique.push(groups[key][0]);
    }
  }

  return unique;
}

通过这种方式，执行所需操作的功能将类似于：

function arrUnique(arr) {
  var groupsById = groupBy("_id", arr);
  var uniqueIds = uniquify(groupsById);
  var groupsByEmail = groupBy("email", uniqueIds);

  return uniquify(groupsByEmail);
}

例如，groupBy("_id", arr)的结果是

{
"jkj238238jdsnfsj23": [
    {
        "_id": "jkj238238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:30:20+00:00"
    },
    {
        "_id": "jkj238238jdsnfsj23",
        "email": "coo@bar.com",
        "firstName": "Ted",
        "lastName": "Jones",
        "address": "456 Neat St",
        "entryDate": "2014-05-07T17:32:20+00:00"
    },
    {
        "_id": "jkj238238jdsnfsj23",
        "email": "bill@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "888 Mayberry St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
],
"edu45238jdsnfsj23": [
    {
        "_id": "edu45238jdsnfsj23",
        "email": "mae@bar.com",
        "firstName": "Ted",
        "lastName": "Masters",
        "address": "44 North Hampton St",
        "entryDate": "2014-05-07T17:31:20+00:00"
    }
],
"wabaj238238jdsnfsj23": [
    {
        "_id": "wabaj238238jdsnfsj23",
        "email": "bog@bar.com",
        "firstName": "Fran",
        "lastName": "Jones",
        "address": "8803 Dark St",
        "entryDate": "2014-05-07T17:31:20+00:00"
    }
],
"sel045238jdsnfsj23": [
    {
        "_id": "sel045238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:32:20+00:00"
    }
],
"qest38238jdsnfsj23": [
    {
        "_id": "qest38238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:32:20+00:00"
    }
],
"vug789238jdsnfsj23": [
    {
        "_id": "vug789238jdsnfsj23",
        "email": "foo1@bar.com",
        "firstName": "Blake",
        "lastName": "Douglas",
        "address": "123 Reach St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
],
"wuj08238jdsnfsj23": [
    {
        "_id": "wuj08238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "Micah",
        "lastName": "Valmer",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
],
"belr28238jdsnfsj23": [
    {
        "_id": "belr28238jdsnfsj23",
        "email": "mae@bar.com",
        "firstName": "Tallulah",
        "lastName": "Smith",
        "address": "123 Water St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
]
}

然后通过_id调用uniqify分组结果：

[
{
    "_id": "jkj238238jdsnfsj23",
    "email": "foo@bar.com",
    "firstName": "John",
    "lastName": "Smith",
    "address": "123 Street St",
    "entryDate": "2014-05-07T17:30:20+00:00"
},
{
    "_id": "edu45238jdsnfsj23",
    "email": "mae@bar.com",
    "firstName": "Ted",
    "lastName": "Masters",
    "address": "44 North Hampton St",
    "entryDate": "2014-05-07T17:31:20+00:00"
},
{
    "_id": "wabaj238238jdsnfsj23",
    "email": "bog@bar.com",
    "firstName": "Fran",
    "lastName": "Jones",
    "address": "8803 Dark St",
    "entryDate": "2014-05-07T17:31:20+00:00"
},
{
    "_id": "sel045238jdsnfsj23",
    "email": "foo@bar.com",
    "firstName": "John",
    "lastName": "Smith",
    "address": "123 Street St",
    "entryDate": "2014-05-07T17:32:20+00:00"
},
{
    "_id": "qest38238jdsnfsj23",
    "email": "foo@bar.com",
    "firstName": "John",
    "lastName": "Smith",
    "address": "123 Street St",
    "entryDate": "2014-05-07T17:32:20+00:00"
},
{
    "_id": "vug789238jdsnfsj23",
    "email": "foo1@bar.com",
    "firstName": "Blake",
    "lastName": "Douglas",
    "address": "123 Reach St",
    "entryDate": "2014-05-07T17:33:20+00:00"
},
{
    "_id": "wuj08238jdsnfsj23",
    "email": "foo@bar.com",
    "firstName": "Micah",
    "lastName": "Valmer",
    "address": "123 Street St",
    "entryDate": "2014-05-07T17:33:20+00:00"
},
{
    "_id": "belr28238jdsnfsj23",
    "email": "mae@bar.com",
    "firstName": "Tallulah",
    "lastName": "Smith",
    "address": "123 Water St",
    "entryDate": "2014-05-07T17:33:20+00:00"
}
]

如果我们现在通过电子邮件对此结果进行分组，我们会得到：

{
"foo@bar.com": [
    {
        "_id": "jkj238238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:30:20+00:00"
    },
    {
        "_id": "sel045238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:32:20+00:00"
    },
    {
        "_id": "qest38238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "John",
        "lastName": "Smith",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:32:20+00:00"
    },
    {
        "_id": "wuj08238jdsnfsj23",
        "email": "foo@bar.com",
        "firstName": "Micah",
        "lastName": "Valmer",
        "address": "123 Street St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
],
"mae@bar.com": [
    {
        "_id": "edu45238jdsnfsj23",
        "email": "mae@bar.com",
        "firstName": "Ted",
        "lastName": "Masters",
        "address": "44 North Hampton St",
        "entryDate": "2014-05-07T17:31:20+00:00"
    },
    {
        "_id": "belr28238jdsnfsj23",
        "email": "mae@bar.com",
        "firstName": "Tallulah",
        "lastName": "Smith",
        "address": "123 Water St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
],
"bog@bar.com": [
    {
        "_id": "wabaj238238jdsnfsj23",
        "email": "bog@bar.com",
        "firstName": "Fran",
        "lastName": "Jones",
        "address": "8803 Dark St",
        "entryDate": "2014-05-07T17:31:20+00:00"
    }
],
"foo1@bar.com": [
    {
        "_id": "vug789238jdsnfsj23",
        "email": "foo1@bar.com",
        "firstName": "Blake",
        "lastName": "Douglas",
        "address": "123 Reach St",
        "entryDate": "2014-05-07T17:33:20+00:00"
    }
]
}

最后在uniqify上应用此结果：

[
{
    "_id": "jkj238238jdsnfsj23",
    "email": "foo@bar.com",
    "firstName": "John",
    "lastName": "Smith",
    "address": "123 Street St",
    "entryDate": "2014-05-07T17:30:20+00:00"
},
{
    "_id": "edu45238jdsnfsj23",
    "email": "mae@bar.com",
    "firstName": "Ted",
    "lastName": "Masters",
    "address": "44 North Hampton St",
    "entryDate": "2014-05-07T17:31:20+00:00"
},
{
    "_id": "wabaj238238jdsnfsj23",
    "email": "bog@bar.com",
    "firstName": "Fran",
    "lastName": "Jones",
    "address": "8803 Dark St",
    "entryDate": "2014-05-07T17:31:20+00:00"
},
{
    "_id": "vug789238jdsnfsj23",
    "email": "foo1@bar.com",
    "firstName": "Blake",
    "lastName": "Douglas",
    "address": "123 Reach St",
    "entryDate": "2014-05-07T17:33:20+00:00"
}
]
相关问题
最新问题