使用 Ramda.js 求和和排序

Question

我有一个对象，它有这样的数字数组对象：

books = [{
  id: "a6113b1cd5d4617f63bb10abc874bea7",
  times: [{
    0: 1,
    1: 5
  }],
  length: 1,
  rating: 4.77,
}, {
  id: "b6113b1cd5d4617f63bb10abc874bea7",
  times: [{
    0: 8
  }],
  length: 1,
  rating: 2.6,
}]

我想添加 按时间排序，但这需要是该对象内所有元素的总和 - 在第一个对象的示例中它是 1+5=6第二个对象是 8，所以排序的最终结果是第一个对象，然后是第二个。这是我到目前为止所拥有的，但它是不完整的。你知道我如何得到数组的总和吗？

const timesSorting =  R.ascend(R.path(['times']))
const sorting = R.sortWith([timesSorting])
sorting(books)

Answer 1

使用R.sortBy，因为您需要按单个属性排序。创建一个获取 time 属性的函数，使用 R.chain 和 R.values 获取时间数组中所有值的数组，并对它们求和。

const { pipe, prop, chain, values, sum, sortBy} = R

const getTimesSum = pipe(prop('times'), chain(values), sum);

const sorting = sortBy(getTimesSum)

const books = [{"id":"a6113b1cd5d4617f63bb10abc874bea7","times":[{"0":1,"1":5}],"length":1,"rating":4.77},{"id":"b6113b1cd5d4617f63bb10abc874bea7","times":[{"0":8}],"length":1,"rating":2.6}]

const result = sorting(books)

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.min.js" integrity="sha512-rZHvUXcc1zWKsxm7rJ8lVQuIr1oOmm7cShlvpV0gWf0RvbcJN6x96al/Rp2L2BI4a4ZkT2/YfVe/8YvB2UHzQw==" crossorigin="anonymous"></script>

如果times始终是一个数组，其中包含具有数字索引的单个对象，您可以将times简化为一个数字数组，然后求和会更容易：

const { pipe, prop, sum, sortBy } = R

const getTimesSum = pipe(prop('times'), sum);

const sorting = sortBy(getTimesSum)

const books = [{
  "id": "a6113b1cd5d4617f63bb10abc874bea7",
  "times": [1, 5], // an array of numbers
  "length": 1,
  "rating": 4.77
}, {
  "id": "b6113b1cd5d4617f63bb10abc874bea7",
  "times": [8], // an array of numbers
  "length": 1,
  "rating": 2.6
}]

const result = sorting(books)

console.log(result)

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.27.1/ramda.min.js" integrity="sha512-rZHvUXcc1zWKsxm7rJ8lVQuIr1oOmm7cShlvpV0gWf0RvbcJN6x96al/Rp2L2BI4a4ZkT2/YfVe/8YvB2UHzQw==" crossorigin="anonymous"></script>

使用 Ramda.js 求和和排序

Sum and sort with Ramda.js

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