Question

我想在一个数组（相同的水果）中找到similair元素并计算总量，例如，我有以下列表：

 val seekBarDrawable = ContextCompat.getDrawable(context, R.drawable.seek_bar_progress)
 val seekBarDrawableLayerDrawable = seekBarDrawable as LayerDrawable
 val ovalItem = seekBarDrawableLayerDrawable.findDrawableByLayerId(R.id.background) as GradientDrawable

        ovalItem.colors = intArrayOf(Color.RED, Color.GREEN)
        ovalItem.gradientType = GradientDrawable.LINEAR_GRADIENT

列表中不应包含数量不同的similair元素（水果），应该像这样：

let array = [
  {
    fruit: "Apple",
    quantity: "2",
  },
  {
    fruit: "Banane",
    quantity: "1",
  },
  {
    fruit: "Kiwi",
    quantity: "5", 
  },
  {
    fruit: "Banane",
    quantity: "2",
  },
  {
    fruit: "Apple",
    quantity: "6",
  },
  {
    fruit: "Ananas",
    quantity: "10",
  },
  {
    fruit: "Apple",
    quantity: "3",
  }
];

我尝试使用过滤器indexOf来获得具有相同水果值的元素，但未成功。什么是正确的解决方案？

Answer 1

这里有一段简短的代码可以满足您的需求，注释会详细说明。

const counts = {} // This will keep track of the counts of each fruit as key value pair
array.forEach(element => {
  if(counts[element.fruit] !== undefined) { // This means that the current fruit have been found before 
    return counts[element.fruit] += Number(element.quantity); // Add the quantity of the current fruit element to the overall summation
  }
  // If the return statement above was not executed, it means that we are seeing the the fruit for the first time
  counts[element.fruit] = Number(element.quantity);
  // Initialize an entry for it in the summations object above, initally set to the current elements quantity
});

// Map the object to become an array again, and overwrite the original array with it if that's desired
array = Object.keys(counts).map(fruit => ({fruit, quantity: counts[fruit]}));

重新排列角度为4的数组中的相似元素

1 个答案: