JSON 和 D3，仅更改子键名但保留父键

Question

In order to make my D3 graphs work correctly, I need the children's names to not be "key" but "label". The parents still need to be "key".

Here is my code and the output. Below that is a couple things I've tried, without success.

Stretch goal, if possible: I don't necessarily want to "hardcode" it either. I'd like to be able to change any level (just the first level in this case) of children's names to whatever I want ("label" in this case).

 var csv = `breakfastItem,gluten,breakfastItemType,month,year,dateCode,value Bagel,Yes,Cinnamon Raisin,May,2017,42856,300 Bagel,Yes,Cinnamon Raisin,March,2017,42795,100 Bagel,Yes,Cinnamon Raisin,November,2016,42675,20 Bagel,Yes,Blueberry,February,2017,42767,50 Bagel,Yes,Blueberry,November,2016,42675,30 Bagel,Yes,Blueberry,March,2016,42430,100 Bagel,Yes,Plain,February,2018,43132,200 Bagel,Yes,Plain,December,2017,43070,202 Bagel,Yes,Plain,February,2016,42401,201`; var data = d3.csvParse(csv, function(d) { d.value = +d.value; d.year = +d.year; d.dateCode = +d.dateCode; return d; }); var breakfastCombinations = d3.nest() .key(function(d) { return d.breakfastItem; }) .key(function(d) { return d.breakfastItemType; }) .rollup(function(oldestDate) { return oldestDate.sort(function(a, b) { return b.dateCode - a.dateCode })[0].value }) .entries(data); console.log(breakfastCombinations)

 <script src="https://d3js.org/d3.v4.min.js"></script>

Example from here is the first thing I looked at.

var expenseMetrics = d3.nest()
  .key(function(d) { return d.name; })
  .rollup(function(v) { return {
    count: v.length,
    total: d3.sum(v, function(d) { return d.amount; }),
    avg: d3.mean(v, function(d) { return d.amount; })
}; })

This second example is something I believe could work, but I'm not sure how to access the children and not just the parent.

breakfastCombinations.forEach(function(d) {
  d.label = d.key;
});

Thanks in advance!

Answer 1

You can use d3.map to map the items:

For example, if you're looking for parent mapping from "key" to "label", use the following:

.entries(data).map(function(group) {
  // parent mapping
  return {label: group.key, values: group.values};
})

 var csv = `breakfastItem,gluten,breakfastItemType,month,year,dateCode,value Bagel,Yes,Cinnamon Raisin,May,2017,42856,300 Bagel,Yes,Cinnamon Raisin,March,2017,42795,100 Bagel,Yes,Cinnamon Raisin,November,2016,42675,20 Bagel,Yes,Blueberry,February,2017,42767,50 Bagel,Yes,Blueberry,November,2016,42675,30 Bagel,Yes,Blueberry,March,2016,42430,100 Bagel,Yes,Plain,February,2018,43132,200 Bagel,Yes,Plain,December,2017,43070,202 Bdagel,Yes,Plain,December,2017,43070,202 Bagel,Yes,Plain,February,2016,42401,201`; var data = d3.csvParse(csv, function(d) { d.value = +d.value; d.year = +d.year; d.dateCode = +d.dateCode; return d; }); var breakfastCombinations = d3.nest() .key(function(d) { return d.breakfastItem; }) .key(function(d) { return d.breakfastItemType; }) .rollup(function(oldestDate) { return oldestDate.sort(function(a, b) { return b.dateCode - a.dateCode })[0].value }) .entries(data).map(function(group) { // parent mapping return {label: group.key, values: group.values}; }) console.log(breakfastCombinations);

 <script src="https://d3js.org/d3.v4.min.js"></script>

And if you're looking for children mapping, use something like this:

.entries(data).map(function(group) {
    // children mapping
    return {key: group.key, values: group.values.map(function(d) { return {label: d.key, value: d.value}})};
})

 var csv = `breakfastItem,gluten,breakfastItemType,month,year,dateCode,value Bagel,Yes,Cinnamon Raisin,May,2017,42856,300 Bagel,Yes,Cinnamon Raisin,March,2017,42795,100 Bagel,Yes,Cinnamon Raisin,November,2016,42675,20 Bagel,Yes,Blueberry,February,2017,42767,50 Bagel,Yes,Blueberry,November,2016,42675,30 Bagel,Yes,Blueberry,March,2016,42430,100 Bagel,Yes,Plain,February,2018,43132,200 Bagel,Yes,Plain,December,2017,43070,202 Bdagel,Yes,Plain,December,2017,43070,202 Bagel,Yes,Plain,February,2016,42401,201`; var data = d3.csvParse(csv, function(d) { d.value = +d.value; d.year = +d.year; d.dateCode = +d.dateCode; return d; }); var breakfastCombinations = d3.nest() .key(function(d) { return d.breakfastItem; }) .key(function(d) { return d.breakfastItemType; }) .rollup(function(oldestDate) { return oldestDate.sort(function(a, b) { return b.dateCode - a.dateCode })[0].value }) .entries(data).map(function(group) { // children mapping return {key: group.key, values: group.values.map(function(d) { return {label: d.key, value: d.value}})}; }) console.log(breakfastCombinations);

 <script src="https://d3js.org/d3.v4.min.js"></script>

Basically, you can use manipulate the array using d3.map as per the requirements.

Hope this helps.