无法对对象数组进行排序

【问题标题】：Not able to sort array of objects无法对对象数组进行排序
【发布时间】：2013-09-06 16:09:57
【问题描述】：

我有以下数组：

[
    {
        "BestCoupon": 1,
        "Saving": "100",
        "Successful": 1,
        "couponCode": "CRIC100",
        "description": "Get Rs. 100 Discount on purchase of Rs. 599 & above. Products include Eyeglasses & Sunglasses and more. Choose",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE :Coupon code \"CRIC200\" is not valid.",
        "Successful": 0,
        "couponCode": "CRIC200",
        "description": "Get Rs. 200 Discount on purchase of Rs. 999 & above. Products include Eyeglasses & Sunglasses and more. Choose",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"CRIC300\" is not valid.",
        "Successful": 0,
        "couponCode": "CRIC300",
        "description": "Get Rs. 300 Discount on purchase of Rs. 1199 & above. Products include Eyeglasses, Sunglasses & Contact Lenses",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE: Coupon code \"JJPREMIUM\" is not valid.",
        "Successful": 0,
        "couponCode": "JJPREMIUM",
        "description": "Get Rs 600 Discount on John Jacobs Eyeglasses. Products include Eyeglasses. Choose from brand like John",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE: Coupon code \"LENS20130303\" is not valid.",
        "Successful": 0,
        "couponCode": "LENS20130303",
        "description": "Get Rs. 500 Discount on purchase of Rs. 1000. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "179.8",
        "Successful": 1,
        "couponCode": "LKEND20",
        "description": "Get 20% Discount on Eyeglasses. Minimum Purchase Rs. 499. Products include Eyeglasses. Choose from brandslike",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "224.75",
        "Successful": 1,
        "couponCode": "LKEND25",
        "description": "Flat 25% off on purchase of Rs 799 & above",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"LKEND30\" is not valid.",
        "Successful": 0,
        "couponCode": "LKEND30",
        "description": "Get 30% Discount on purchase of Rs 1299 & above. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"LKEND35\" is not valid.",
        "Successful": 0,
        "couponCode": "LKEND35",
        "description": "Get 35% Discount on purchase of Rs 1499 & above. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "100",
        "Successful": 1,
        "couponCode": "OMGABV600",
        "description": "Get Rs. 100 Discounton order of Rs. 600 & Above. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"POWERSUN20\" isnot valid.",
        "Successful": 0,
        "couponCode": "POWERSUN20",
        "description": "Get 20% OFFon Power Sunglasses. Select from a vast collection.",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "179.8",
        "Successful": 1,
        "couponCode": "WEEKEND20",
        "description": "Flat 20% OFF on purchase of Rs 499 & above - NA on Premium Brands & Contact Lenses",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    }
]

我想按“储蓄”的降序对其进行排序。我正在使用以下代码

couponObj.sort(function (a, b) {
      if (a[0].Saving == b[0].Saving)
         return 0;
      if (a[0].Saving > b[0].Saving)
         return -1;
      if (a[0].Saving < b[0].Saving)
         return 1;
});

它给了我以下结果：

[
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"POWERSUN20\" is not valid.",
        "Successful": 0,
        "couponCode": "POWERSUN20",
        "description": "Get 20% OFF on Power Sunglasses. Select from a vast collection.",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"LKEND35\" is not valid.",
        "Successful": 0,
        "couponCode": "LKEND35",
        "description": "Get 35% Discount on purchase of Rs 1499 & above. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"LKEND30\" is not valid.",
        "Successful": 0,
        "couponCode": "LKEND30",
        "description": "Get 30% Discount on purchase of Rs 1299 & above. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"LENS20130303\" is not valid.",
        "Successful": 0,
        "couponCode": "LENS20130303",
        "description": "Get Rs. 500 Discount on purchase of Rs. 1000. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"JJPREMIUM\" is not valid.",
        "Successful": 0,
        "couponCode": "JJPREMIUM",
        "description": "Get Rs 600 Discount on John Jacobs Eyeglasses. Products include Eyeglasses. Choose from brand like John",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"CRIC300\" is not valid.",
        "Successful": 0,
        "couponCode": "CRIC300",
        "description": "Get Rs. 300 Discount on purchase of Rs. 1199 & above. Products include Eyeglasses, Sunglasses & Contact Lenses",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "NOT APPLICABLE : Coupon code \"CRIC200\" is not valid.",
        "Successful": 0,
        "couponCode": "CRIC200",
        "description": "Get Rs. 200 Discount on purchase of Rs. 999 &above. Products include Eyeglasses & Sunglasses and more. Choose",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "224.75",
        "Successful": 1,
        "couponCode": "LKEND25",
        "description": "Flat 25% off on purchase of Rs 799 & above",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "179.8",
        "Successful": 1,
        "couponCode": "LKEND20",
        "description": "Get 20% Discount on Eyeglasses. Minimum Purchase Rs. 499. Products include Eyeglasses. Choose from brands like",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "179.8",
        "Successful": 1,
        "couponCode": "WEEKEND20",
        "description": "Flat 20%OFF on purchase of Rs 499 & above - NA on Premium Brands & Contact Lenses",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "100",
        "Successful": 1,
        "couponCode": "CRIC100",
        "description": "Get Rs. 100 Discount on purchase of Rs. 599 & above. Products include Eyeglasses & Sunglasses and more. Choose",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    },
    {
        "BestCoupon": 0,
        "Saving": "100",
        "Successful": 1,
        "couponCode": "OMGABV600",
        "description": "Get Rs. 100 Discount on order of Rs. 600 & Above. Products include Eyeglasses, Sunglasses & Contact Lenses and",
        "domain": "www.lenskart.com",
        "url": "http://www.lenskart.com/checkout/cart/"
    }
]

基本上，它在保存为字符串的数组项的顶部进行排序。我希望它们在底部。

【问题讨论】：

  • 这是一个对象数组，不是 Json 字符串
  • 为什么使用a[0].Saving而不是a.Saving？
  • 我已编辑您的问题以删除对 JSON 的引用，因为它似乎与它没有任何关系。如果我错了，请随时纠正。
  • 一个小建议：有一个名为 SavingText 的附加键并将“不适用”文本移动到那里并将 Saving 设置为 0。
  • 如果你对他们在说什么感到困惑，JSON 是一种将数据放入字符串中以进行传输的方式，而对象是 JavaScript 中实际数据结构的使用方式

标签： javascript sorting


【解决方案1】：

当比较器函数提供给Array.prototype.sort 时，它被赋予参数a 和b，它们是原始数组的元素，而不是数组本身。

因此，在这种特殊情况下，您需要删除 [0]。例如，而不是：

if (a[0].Saving == b[0].Saving) { ...

尝试：

if (a.Saving === b.Saving) { ...
           // ^-- also, it's best to use strict comparison

【讨论】：

    【解决方案2】：

    看起来您正在尝试访问似乎不存在的对象的属性0；并在纠正它的同时，更容易看到发生了什么。

    couponObj.sort(function (a, b) {
    a = +a.Saving, b = +b.Saving; // cast Number
    // special cases
    if (a !== a || b !== b)           // If there is a NaN
        return (a !== a) - (b !== b); // move it to the end
    // classic descending sort
    return b - a;
});

    【讨论】：

    • +1 为什么不是经典的return b - a？ JS有什么不同吗？
    • 我问是因为人们永远无法知道像 JS 这样的弱类型语言......也许有一些隐藏的东西（比如你使用 ===，但至少我知道）
    • 考虑到他有各种 NaN 值（“文本”值），也许将它们作为特殊情况处理会更好:-)
    • @xanatos 我们知道这个例子很好，因为我已经做了演员表。您可能需要考虑如果没有演员表是否可以并且您期望不同的类型
    • NaN 不会被移动，真的。让我解决这个问题。
    【解决方案3】：

    正如其他人所建议的那样，但需要注意的是：您有各种 Saving 是文本而不是描述...

    couponObj.sort(function (a, b) {
    a = parseFloat(a.Saving); // cast to number
    b = parseFloat(b.Saving); // cast to number

    if (isNaN(a)) return isNaN(b) ? 0 : 1;
    if (isNaN(b)) return -1;

    return b - a; // descending order
});

    当您尝试使用+ 将非数字转换为数字时，返回的数字是NaN（一个不能很好排序的特殊值）。为此各种if (isNaN())

    请注意，在初始版本中，我使用+a.Saving 将字符串转换为数字，但我已将其更改为parseFloat。 null 有细微的差别：+null === 0，而parseFloat(null) === NaN（那我可以处理）。

    【讨论】：

    • 希望a 和b 不是null ;)
    • @Oleg +null 为 0...mmmmh
    • +null.Saving -> "TypeError: Cannot read property 'Saving' of null" 因为在尝试“强制转换”为数字之前将读取该属性。
    • @Oleg Ah... 不，我在想a.Saving 可能是null 或undefined
    • 看起来漂亮整洁。示例 JSON 没有任何 null 条目，所以我认为我们不需要担心，除非它得到 OP 的说明
    【解决方案4】：

    使用 parseFloat 方法将字符串转换为浮点数：

    couponObj.sort(function (a, b) {
  if(a && b) {
    var af = parseFloat(a.Saving);
    var bf = parseFloat(b.Saving);
    if(isNan(af)) return 1;
    if(isNan(bf)) return -1;
    return bf-af;
  }
  return 0; // ignore null entries
}

    【讨论】：

      猜你喜欢
      相关资源
      最近更新 更多
      热门标签
      Java Python linux javascript C# Mysql Docker 算法 前端 SpringBoot Redis Vue spring .net 设计模式 .net core c++ kubernetes 数据库 机器学习 大数据 数据结构 微服务 js 人工智能 Go Android 面试 程序员 JVM 云原生 后端 ASP.net core 深度学习 CSS k8s git golang PHP devops Nginx Django React mybatis 架构 多线程 Spring Boot 云计算 LeetCode 分布式