如何通过忽略微小差异来使用lodash进行分组

Question

我有以下表格的数据。我正在逐行使用loadash for groupby。但是，loadash groupby是基于行值返回组，我期望它应该忽略行之间的1个值的小差异然后分组。恩。它应该在一个组中添加第9行和第10行的项目。我应该从groupby回调函数返回什么，它将通过包含相邻值来对属性进行分组。

[
  {
    "row": 9,
    "city": "Camas"
  },
  {
    "row": 9,
    "city": "Kersey"
  },
  {
    "row": 6,
    "city": "Ebro"
  },
  {
    "row": 10,
    "city": "Orick"
  },
  {
    "row": 2,
    "city": "Bonanza"
  },
  {
    "row": 6,
    "city": "Rowe"
  },
  {
    "row": 5,
    "city": "Walland"
  }
]

预期产出

 {
    2: [
        {
            "row": 2,
            "city": "Bonanza"
        },
    ],
    5: [
        {
            "row": 6,
            "city": "Ebro"
        },
        {
            "row": 6,
            "city": "Rowe"
        },
        {
            "row": 5,
            "city": "Walland"
        }
    ],
    9: [{
        "row": 9,
        "city": "Camas"
    },
    {
        "row": 9,
        "city": "Kersey"
    },
    {
        "row": 10,
        "city": "Orick"
    }
    ]
}

Answer 1

解决此问题的一种方法是sort按row按升序排列，然后reduce排序集合，方法是将行差异合并为1并简单地指定那些没有的人。

var result = _(data)
  .sortBy('row')
  .reduce(function(group, item) {
    var nIndex = item.row - 1;
    var value = [item];
    if (group[nIndex]) {
      group[nIndex] = value.concat(group[nIndex]);
    } else {
      group[item.row] = value;
    }
    return group;
  }, {});

var data = [{
    "row": 9,
    "city": "Camas"
  },
  {
    "row": 9,
    "city": "Kersey"
  },
  {
    "row": 6,
    "city": "Ebro"
  },
  {
    "row": 10,
    "city": "Orick"
  },
  {
    "row": 2,
    "city": "Bonanza"
  },
  {
    "row": 6,
    "city": "Rowe"
  },
  {
    "row": 5,
    "city": "Walland"
  }
];

var result = _(data)
  .sortBy('row')
  .reduce(function(group, item) {
    var nIndex = item.row - 1;
    var value = [item];
    if (group[nIndex]) {
      group[nIndex] = value.concat(group[nIndex]);
    } else {
      group[item.row] = value;
    }
    return group;
  }, {});

console.log(result);

body>div {
  min-height: 100%;
  top: 0;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.js"></script>

上述解决方案也可以使用vanilla JS Array#sort和Array#reduce

来实现

var result = data
  .sort(function(v1, v2) {
    return v1.row - v2.row;
  })
  .reduce(function(group, item) {
    var nIndex = item.row - 1;
    var value = [item];
    if (group[nIndex]) {
      group[nIndex] = value.concat(group[nIndex]);
    } else {
      group[item.row] = value;
    }
    return group;
  }, {});

var data = [{
    "row": 9,
    "city": "Camas"
  },
  {
    "row": 9,
    "city": "Kersey"
  },
  {
    "row": 6,
    "city": "Ebro"
  },
  {
    "row": 10,
    "city": "Orick"
  },
  {
    "row": 2,
    "city": "Bonanza"
  },
  {
    "row": 6,
    "city": "Rowe"
  },
  {
    "row": 5,
    "city": "Walland"
  }
];

var result = data
  .sort(function(v1, v2) {
    return v1.row - v2.row;
  })
  .reduce(function(group, item) {
    var nIndex = item.row - 1;
    var value = [item];
    if (group[nIndex]) {
      group[nIndex] = value.concat(group[nIndex]);
    } else {
      group[item.row] = value;
    }
    return group;
  }, {});

console.log(result);

body>div {
  min-height: 100%;
  top: 0;
}