javascript - 如何从多维数组中提取值以形成另一个数组？

Question

所以我有一个包含 4 个值的数组：项目、类别、已检查、编号：

var MyArray = [
["coke", "beverages", "checked", 000],
["baguette", "bread", "checked", 001],
["water", "beverages", "checked", 000],
["pepsi", "beverages", "checked", 000],
["wholemeal", "bread", "checked", 001],
...
]

我如何制作更多的数组来对它们进行分类，如下所示：

var beverages = ["coke", "pepsi", "water"]; // more drinks from above array...
var bread = ["baguette", "wholemeal"]; // more types of bread from above array...

任何帮助将不胜感激，谢谢！

标签： javascriptarrays

Answer 1

您可以reduce像这样对项目进行分组。创建一个以每种食物为键的累加器对象。Destructure每个内部数组获取第一项和第二项。

var MyArray = [
  ["coke", "beverages", "checked", 000],
  ["baguette", "bread", "checked", 001],
  ["water", "beverages", "checked", 000],
  ["pepsi", "beverages", "checked", 000],
  ["wholemeal", "bread", "checked", 001],
]

const grouped = MyArray.reduce((r, [item, type]) => {
  r[type] = r[type] || [];
  r[type].push(item)
  return r;
}, {})

const { bread, beverages } = grouped

console.log(bread, beverages)

这就是grouped对象的外观。您可以使用解构来获取更多类别的食物

{
  "beverages": [ "coke", "water", "pepsi" ],
  "bread": [ "baguette", "wholemeal" ]
}