从循环中向JavaScript数组添加项

Question

我希望用循环中的新数据替换这个静态数组。

var tabledata = [
  { sku:'442398GE', asin:'B075MJ6TPK', current_week_rating: 4.5, wk9: 4.0, wk8: 4.1, wk7: 3.1, wk6: 1.1, total_ratings: 991 },
  { sku:'502764GE', asin:'B07NFLRN23', current_week_rating: 5.0, wk9: 3.2, wk8: 3.2, wk7: 5.0, wk6: 2.1, total_ratings: 389 },
  { sku:'502764GE', asin:'B07NFLRN23', current_week_rating: 4.2, wk9: 4.0, wk8: 3.0, wk7: 4.1, wk6: 3.7, total_ratings: 22 },
  { sku:'442398GE', asin:'B07NFLRN23', current_week_rating: 4.2, wk9: '', wk8: 4.8, wk7: 4.1, wk6: 4.1, total_ratings: 832 },
  { sku:'502764GE', asin:'B07NFLRN23', current_week_rating: 2.2, wk9: 1.5, wk8: 1.5, wk7: 4.1, wk6: 4.1, total_ratings: 103 },
  { sku:'442398GE', asin:'B07NFLRN23', current_week_rating: 4.2, wk9: 5.0, wk8: 5.0, wk7: 4.1, wk6: 4.1, total_ratings: 382 },
  { sku:'502764GE', asin:'B07NFLRN23', current_week_rating: 4.2, wk9: 4.0, wk8: 4.0, wk7: 4.1, wk6: 4.1, total_ratings: 111 },
  { sku:'442398GE', asin:'B07NFLRN23', current_week_rating: 1.2, wk9: 4.0, wk8: 4.0, wk7: 4.1, wk6: 4.1, total_ratings: 226 },
];

我从静态数组中删除了所有项，并创建了一个空白的tabledata变量/数组：var tabledata = [];

var tabledata = [];

var i;
for (i = 0; i < phpjs.amazon_ratings.length; i++) {
  tabledata.sku = phpjs.amazon_ratings[i].sku;
  tabledata.asin = phpjs.amazon_ratings[i].asin;
  tabledata.current_week_rating = phpjs.amazon_ratings[i].rating;
  tabledata.wk9 = '4.5'; // static for now, can be ignored.
  tabledata.wk8 = '4.0'; // static for now, can be ignored.
  tabledata.wk7 = '4.8'; // static for now, can be ignored.
  tabledata.wk6 = '3.0'; // static for now, can be ignored.
  tabledata.total_ratings = phpjs.amazon_ratings[i].ratings_total;
}

console.log(tabledata);

以下是控制台日志的结果：

[sku: "448741GE", asin: "B001AH2LKE", current_week_rating: "4.7", wk9: "4.5", wk8: "4.0", …]

所以，我可以告诉你，它每次都是压倒一切的，只剩下最后一次。假设我需要将[i]键添加到循环项中，但还不确定在哪里。尝试但失败：tabledata[i]

Answer 1

若要向数组添加项，应使用推()方法。您的代码看起来会是这样的：

var tabledata = [];

var i;
for (i = 0; i < phpjs.amazon_ratings.length; i++) {
  // Create the item object
  var item = {};
  item.sku = phpjs.amazon_ratings[i].sku;
  item.asin = phpjs.amazon_ratings[i].asin;
  item.current_week_rating = phpjs.amazon_ratings[i].rating;
  item.wk9 = '4.5'; // static for now, can be ignored.
  item.wk8 = '4.0'; // static for now, can be ignored.
  item.wk7 = '4.8'; // static for now, can be ignored.
  item.wk6 = '3.0'; // static for now, can be ignored.
  item.total_ratings = phpjs.amazon_ratings[i].ratings_total;

  // Add it to the array
  tabledata.push(item);
}

console.log(tabledata);

另一种方法是使用地图()方法，它使代码更简洁，IMHO。在本例中，代码如下所示：

var tabledata = phpjs.amazon_ratings.map(item => {
  return {
    'sku': item.sku,
    'asin': item.asin,
    'current_week_rating': item.rating,
    'wk9': 4.5,
    'wk8': 4.0,
    'wk7': 4.8,
    'wk6': 3.0,
    'total_ratings': item.ratings_total
  };
});
console.log(tabledata);