[D3] Load and Inspect Data with D3 v4

You probably use a framework or standalone library to load data into your apps, but what if that’s overkill for your needs? What if you’re just putting together a quick demo? This lesson demonstrates D3’s APIs for loading data on its own, as well as some helpful methods for inspecting your data and preparing it for use with D3.

 

function loadData() {
    d3.json('data/data.json', function(data) {
        var extent = d3.extent(data, function (d) {
            return d.age
        }); // get the value range
        console.log("#Extent", extent);

        var min = d3.min(data, function (d) {
            return d.age
        });
        console.log("#Min", min);

        var max = d3.max(data, function (d) {
            return d.age
        });
        console.log("#Max", max);

        var ages = d3.set(data, function(d) {
            return d.age
        }); // get unique value out of data
        console.log("#Ages", ages.values());

        var scale = d3.scaleLinear()
            .domain(extent)
            .range([0,100]);

        console.log(scale(23))
    })
}

 

转载于:https://www.cnblogs.com/Answer1215/p/6166022.html