CODEWITHSUNDEEP
javascriptd3.js
haneulkim
haneulkim

Reputation: 4928

How to convert multiple d3.csv data into number?

right now after loading csv file I am looping each object within an array and converting one by one.

which looks like

fulldata.forEach(function(data){
      data.healthcare = +data.healthcare;
      data.a = +data.a;
      data.b = +data.b;
      data.c = +data.c;
    })

assume there are about 100 feature that you need to convert into number, is there a way that convert multiple feature into number at once?

Upvotes: 2

Views: 3147

Answers (2)

Gerardo Furtado
Gerardo Furtado

Reputation: 102219

D3 v5 introduced a very convenient method, called d3.autoType, which:

For each value in the given object, the trimmed value is computed; the value is then re-assigned as follows:

  1. If empty, then null.
  2. If exactly "true", then true.
  3. If exactly "false", then false.
  4. If exactly "NaN", then NaN.
  5. Otherwise, if coercible to a number, then a number.
  6. Otherwise, if a date-only or date-time string, then a Date.
  7. Otherwise, a string (the original untrimmed value).

It is very handy when you don't have all columns as a numeric value. For instance, using d3.csvParse, you just need:

const fullData = d3.csvParse("your_CSV_URL_here", d3.autoType);

Here is a demo:

const csv = `number,string,date
32,foo,2019-01-21
47,bar,2018-11-19
17,baz,2019-07-28`;

const data = d3.csvParse(csv, d3.autoType);

console.log(data)
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.9.0/d3.min.js"></script>

However, if in fact you have all columns as numeric values, just get all properties inside the row function:

const csv = `foo,bar,baz
12,43,23
75,44,32
76,93,23`;

const data = d3.csvParse(csv, function(d) {
  d3.keys(d).forEach(function(e) {
    d[e] = +d[e]
  })
  return d;
});

console.log(data)
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>

Upvotes: 4

Julian W.
Julian W.

Reputation: 1571

You can use Object.keys() to get an array of features.

fulldata.forEach(function(data) {
  Object.keys(data).forEach(function(key) {
    data[key] = +data.key;
  });
})

Upvotes: 0

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