d3.js：排序嵌套数组

Question

How can I sort the nested arrays of an array like the one below please? I would like to sort array prob and then rearrange name accordingly so that relationship is maintained.

var records = [
{ num: 1, name: ["Sam", "Amy", "John"], prob: [0.3, 0.2, 0.5]},
{ num: 2, name: ["Nick", "Carol", "Sam"], prob: [0.5, 0.03, 0.47] },
{ num: 3, name: ["Ken", "Eric", "Ely"], prob: [0.1, 0.3, 0.6] },
{ num: 4, name: ["Amy", "Sam", "John"], prob: [0.6, 0.3, 0.1] },
{ num: 5, name: ["Chris", "Donna", "Jeff"], prob: [0.25, 0.55, 0.2] }
]

I would like to end-up with:

var records = [
{ num: 1, name: ["John", "Sam", "Amy"], prob: [0.5, 0.3, 0.2]},
{ num: 2, name: ["Nick", "Sam", "Carol"], prob: [0.5, 0.47, 0.03] },
{ num: 3, name: ["Ely", "Eric", "Ken"], prob: [0.6, 0.3, 0.1] },
{ num: 4, name: ["Amy", "Sam", "John"], prob: [0.6, 0.3, 0.1] },
{ num: 5, name: ["Donna", "Chris", "Jeff"], prob: [0.55, 0.25, 0.2] }
]

Thanks!

Answer 1

It's easiest if you turn your arrays of name s and prob s into objects to preserve the links between each name and the probability. The object's properties can then be sorted as if they were an array using a custom sort function.

records.forEach( function (d) {
  var temp = {};

  // create objects with key <name> and value <prob>
  // (this makes the assumption that prob values may not be unique, but names are)
  d.name.forEach( function(e,i) {
    temp[e] = d.prob[i];
  })

  // get an array of the object keys (the name), and sort them by the object values
  // (the corresponding prob), descending. Replace the existing `name` array with this.
  d.name = Object.keys(temp).sort(function(a, b){ 
    return temp[b] - temp[a];
  });

  // sort the prob values in descending order (with d3.descending, since you mentioned d3)
  d.prob = d.prob.sort(function(a,b){ return b - a; });
});

If you aren't using d3, replace d3.descending with the standard descending sort function.

Answer 2

Here a solution: we could store names and prob in pairs and sorting both values at the same time, then we assign that names and probs sorted to the main object:

 var records = [ { num: 1, name: ["Sam", "Amy", "John"], prob: [0.3, 0.2, 0.5]}, { num: 2, name: ["Nick", "Carol", "Sam"], prob: [0.5, 0.03, 0.47] }, { num: 3, name: ["Ken", "Eric", "Ely"], prob: [0.1, 0.3, 0.6] }, { num: 4, name: ["Amy", "Sam", "John"], prob: [0.6, 0.3, 0.1] }, { num: 5, name: ["Chris", "Donna", "Jeff"], prob: [0.25, 0.55, 0.2] } ]; var pairs = records.map((e,i)=> e.name.map((e2,i2)=>[e2,records[i].prob[i2]]).sort((a,b)=>b[1]-a[1]) ); records.map((e, i) => { e.name = pairs[i].map(o => o[0]) e.prob = pairs[i].map(o => o[1]) }) console.log(records) 

Answer 3

Refactoring Emeeus answer

 var records = [ { num: 1, name: ["Sam", "Amy", "John"], prob: [0.3, 0.2, 0.5]}, { num: 2, name: ["Nick", "Carol", "Sam"], prob: [0.5, 0.03, 0.47] }, { num: 3, name: ["Ken", "Eric", "Ely"], prob: [0.1, 0.3, 0.6] }, { num: 4, name: ["Amy", "Sam", "John"], prob: [0.6, 0.3, 0.1] }, { num: 5, name: ["Chris", "Donna", "Jeff"], prob: [0.25, 0.55, 0.2] } ]; records.forEach((e, i) => { var el = e.name.map((e2,i2)=>[e2,e.prob[i2]]); el.sort((a, b) => b[1] - a[1]); e.name = el.map(o => o[0]); e.prob = el.map(o => o[1]); }); console.log(records);