transpose(object)?

未关闭
  • 哪里不对？
#48 3 条评论 1 个 reaction 已指派 0 人 在 GitHub 查看

维护者通常 1 天内回复

还没有人认领这个 Issue。

  • #158 来自 @Fil —— 已关闭，未合并

评估

难度
5/5
预计耗时
一周以上
新手友好度
20/100
Issue 类型
功能
描述清晰度
需要澄清
活跃度
停滞
技术栈
javascript
领域
data

调研方向

Read the existing transpose documentation in README.md and inspect the current d3.transpose implementation. The issue asks whether to overload it or introduce a separately named method, including behavior for both object-of-arrays and array-of-objects; settle the API and expected edge cases before implementation. Done means the chosen behavior is documented and covered by tests, but this issue gives no test file or decision on the API.

由索引模型根据 Issue 内容生成。

描述

We have transpose(matrix) which transposes the rows and columns of a matrix (an array of arrays). But you might want similar functionality to transpose an object whose values are arrays into an array whose elements are objects.

function transpose(object) {
  var m = 0;
  for (var k in object) m = Math.max(m, object[k].length);
  for (var i = -1, transpose = new Array(m); ++i < m;) {
    var o = transpose[i] = {};
    for (var k in object) {
      o[k] = object[k][i];
    }
  }
  return transpose;  
}

Where:

transpose({
  year: [2001, 2002],
  value: [1, 2]
})

Returns:

[
  {year: 2001, value: 1},
  {year: 2002, value: 2},
]

Should we try to overload d3.transpose to do both?

If so, how? The above implementation sort-of works for array-of-array input such as transpose([[0, 1, 2], [3, 4, 5]]), but returns an array of objects rather than an array of arrays. You could use Array.isArray to test whether the input is an Array and branch the behavior accordingly.

If not, what name should this new method have? transposeObject?

Also, if transpose(object) given an object whose values are arrays returns an array of objects, then transpose(array) given an array whose elements are objects should return an object whose values are arrays.

Maybe this is too magical.

主要语言
JavaScript
星标
465
派生
193
平均合并
5 小时 46 分钟
30 天内合并 PR
1

环境准备

这个项目没有提供开发容器、Dockerfile 或贡献指南，环境需要你自己搭建：先看它的 README，通用步骤见我们的新手贡献指南。

从这里开始

  1. 先读完整个 Issue，再读项目的贡献指南。
  2. 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
  3. Fork 仓库，在一个分支上完成修改。
  4. 提交 Pull Request，并在描述里引用这个 Issue 编号。

d3/d3-array 的其他 Issue

查看 d3/d3-array 的全部 Issue

相似的 Issue

更多 JavaScript Issue

把新 issue 发到你的邮箱

精选适合新手参与的 GitHub issue 摘要。