Question

我有一个要按年份分组的数组。例如，我在数组中有6个条目，并想创建一个按年份分组的二维数组，因此每年有2个条目...

[4711.067999999985, 12596.399999999936, 12596.399999999936, "Accessories", "2011"]
[5277939.947800145, 8912342.140000183, 8912342.140000183, "Bikes", "2011"]
[16185.937500000333, 42468.34000000009, 42468.34000000009, "Accessories", "2012"]
[11725882.954398958, 19702448.459998813, 19702448.459998813, "Bikes", "2012"]
[168010.80079996982, 448815.8899998886, 448815.8899998886, "Accessories", "2013"]
[14915767.767399808, 24907912.949997608, 24907912.949997608, "Bikes", "2013"]

我希望这是一个类似于...的数组

Array[0][0] = [4711.067999999985, 12596.399999999936, 12596.399999999936, "Accessories", "2011"]

Array[0][1] = [5277939.947800145, 8912342.140000183, 8912342.140000183, "Bikes", "2011"]

Array[1][0] = [16185.937500000333, 42468.34000000009, 42468.34000000009, "Accessories", "2012"]

所以Array[0]是2011，Array[1]是2012，Array[2]是2013，等等。

有什么想法如何遍历数组然后按年份分组吗？

Answer 1

我建议使用JSON格式保存您的数据（将JavaScript作为对象可以很好地工作）。看起来像这样：

{
  "years": [
    {
      "id": 2011, 
      "value01": 4711.067999999985, 
      "value02": 12596.399999999936, 
      "value03": 12596.399999999936, 
      "type": "Accessories"
    }, 
    {
      "year": 2012, 

      ...

    }
  ]
}

否则，您仅可以将每个值组合保存为一个字符串，这不是以后使用的最佳解决方案。您可以在w3schools上找到更多信息。

Answer 2

let data = [ 
  [4711.067999999985, 12596.399999999936, 12596.399999999936, "Accessories", "2011"],
  [5277939.947800145, 8912342.140000183, 8912342.140000183, "Bikes", "2011"],
  [16185.937500000333, 42468.34000000009, 42468.34000000009, "Accessories", "2012"],
  [11725882.954398958, 19702448.459998813, 19702448.459998813, "Bikes", "2012"],
  [168010.80079996982, 448815.8899998886, 448815.8899998886, "Accessories", "2013"],
  [14915767.767399808, 24907912.949997608, 24907912.949997608, "Bikes", "2013"]
]

yearsList= ['2011', '2012', '2013']

groupByYear = {}

yearsList.map((year, index) => {
  groupByYear[index] = [];
  data.map(item => { 
    if(item.includes(year)){
      groupByYear[index].push(item)
    }
  })
})

console.log("groupBy Year", groupByYear, "\n**********END\n\n")

// If you want in 2D array then

let output = Object.values(groupByYear)

console.log("Year 2011 data", output[0]);
console.log("Year 2012 data", output[1]);
console.log("Year 2013 data",output[2]);

Answer 3

您可以使用哈希表在O（n）中解决该问题：

  const results = [], hash = {};

  for(const [v1, v2, v3, category, year] of input) {
    if(!hash[year]) {
      results.push(hash[year] = []);
    }
    hash[year].push([v1, v2, v3, category, year]);
 }

根据年份从数组创建分组数组

3 个答案: