D3.js nest.sortKeys()函数

D3.js 是一个用 JavaScript 构建的库，专门用于数据可视化。 nest.sortKeys()函数用于按特定顺序（即升序或降序）对键进行排序。

句法：

nest.sortkeys( comparatorFunction )

参数：此函数接受一个参数comparatorFunction ，用于指定如何对键进行排序。如果没有为当前键指定comparatorFunction，则未定义键的返回顺序。

返回值：根据比较器函数返回排序后的键（升序/降序）。

下面的程序说明了 D3.js 中的 nest.sortKeys()函数。

示例 1：

HTML

  

    
    
  
    
    
  
    
        D3.js nest.sortKeys() Function
    

  

    
          
        // Dataset
        var cars = [
            { name: "car1", manufactured: "1950", model: "s51" },
            { name: "car1", manufactured: "1952", model: "s51" },
            { name: "car1", manufactured: "1951", model: "s50" },
            { name: "car1", manufactured: "1953", model: "s52" },
            { name: "car1", manufactured: "1953", model: "s50" },
            { name: "car1", manufactured: "1950", model: "s52" },
        ];
  
        var groupedData = d3.nest()
            .key(function (d) { return d.manufactured; })
  
            // sorting keys in ascending order
            .sortKeys(d3.ascending)
            .entries(cars);
        console.log("ArrayData :", groupedData);
    

  

输出：

按升序排序的键

示例 2：

HTML

  

    
    
  
    
    
  
    
        D3.js nest.sortKeys() Function
    

  

    
        var cars = [
            { name: "car1", manufactured: "1950", model: "s51" },
            { name: "car1", manufactured: "1952", model: "s51" },
            { name: "car1", manufactured: "1951", model: "s50" },
            { name: "car1", manufactured: "1953", model: "s52" },
            { name: "car1", manufactured: "1953", model: "s50" },
            { name: "car1", manufactured: "1950", model: "s52" },
        ];
        var groupedData = d3.nest()
            .key(function (d) { return d.manufactured; })
  
            // Sorting keys in descending order
            .sortKeys(d3.descending)
            .entries(cars);
        console.log("ArrayData :", groupedData);
    

  

输出：

按降序排列的键