javascript - 如何在 JavaScript 中区分值和二维数组

Question

我得到了一个由数据库填充的二维数组，如下所示:

var Index = [["value1_lang1", "value1_lang2", "value1_lang3", "3,6,11,"],["value1_lang1", "value1_lang2", "value1_lang3", "37,41,97,114,"],["value2_lang1", "value2_lang2", "value2_lang3", "9,14,33,"]];

该数组将获得超过 600 个值。我尝试使用以下两个 for 循环来完成此操作:

for(var i = 0; i < Index.length; i++) {
 for(var j = i + 1; j < Index.length; ) {
  var item1 = Index[i][0]; //Only have to compare the values from lang1
  var item2 = Index[j][0];

  if(item1 == item2) {
   var page1 = Index[i][3];
   var page2 = Index[j][3];

   if(page1 != page2) {
    var newpages = page1 + page2;
   } else {
    var newpages = page1;
   }

   Index[i][3] = newpages;
   Index.splice(j, 1);
   page1 = "";
   page2 = "";
   newpages = "";

  } else {
   j++;
  }
 }
}

结果应如下所示:

var Index = [["value1_lang1", "value1_lang2", "value1_lang3", "3,6,11,37,41,97,114"], ["value2_lang1", "value2_lang2", "value2_lang3", "9,14,33,"]];

但真正的结果是这样的:

var Index = [[undefined, undefined, undefined, undefined],["value1_lang1", "value1_lang2", "value1_lang3", "3,6,11,37,41,97,114,"], ["value2_lang1", "value2_lang2", "value2_lang3", "9,14,33,"]];

Answer 1

您可以使用内部数组的前三个元素作为哈希表的键，并推送到结果集(如果不存在)或将元素附加到索引 3 处。

var data = [["value1_lang1", "value1_lang2", "value1_lang3", "3,6,11,"], ["value1_lang1", "value1_lang2", "value1_lang3", "37,41,97,114,"], ["value2_lang1", "value2_lang2", "value2_lang3", "9,14,33,"]],
    result = [];

data.forEach(function (a) {
    var key = a.slice(0, 3).join('|');
    if (!this[key]) {
        this[key] = a.slice();
        result.push(this[key]);
        return;
    }
    this[key][3] += a[3];
}, Object.create(null));

console.log(result);

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