D3.js threshold.copy()函数

d3.js 中的threshold.copy()函数用于创建和返回阈值比例的精确副本。原始比例的任何更改都不会影响复制比例。

句法：

threshold.copy();

参数：此函数不接受任何参数。

返回值：此函数返回原始阈值比例的精确副本。

示例 1：

HTML

  

    
    
  
    
    

  

    GeekforGeeks
  
    threshold.copy() Function 
  
    
        var threshold = d3.scaleThreshold()
            // Domain
            .domain([1, 2, 3, 4])
            // Range for the domain
            .range([10, 20, 30, 40, 50]);
  
        document.write("<h3>threshold(1): " 
            + threshold(1) + "</h3>");
        document.write("<h3>threshold(3): " 
            + threshold(3) + "</h3>");
  
        document.write(
            "<p> This is from copy scale.</p>");
  
        var thresholdCopy = threshold.copy();
          
        document.write("<h3>thresholdCopy(1): " 
            + thresholdCopy(1) + "</h3>");
        document.write("<h3>thresholdCopy(3): " 
            + thresholdCopy(3) + "</h3>");
    

  

输出：

示例 2：

HTML

  

    
    
  
    
    

  

    GeekforGeeks
  
    threshold.copy() Function 
  
    
        var threshold = d3.scaleThreshold()
            // Domain
            .domain([1, 2, 3, 4])
            // Range for the domain
            .range([10, 20, 30, 40, 50]);
  
        var thresholdCopy = threshold.copy();
  
        document.write(
            "<div style=line-height:5px><h3>threshold(1): " 
            + threshold(1) + "</h3>");
  
        document.write("<h3>threshold(3): " 
                + threshold(3) + "</h3>");
  
        // Making changes on the original scale
        threshold.range([100, 200, 300, 400, 500]);
        document.write(
        "<p> After making changes in the original scale</p>");
  
        document.write("<h3>threshold(3): " 
                + threshold(3) + "</h3>");
  
        document.write("<p> This is from copy scale.</p>");
  
        document.write("<h3>thresholdCopy(1): " 
                + thresholdCopy(1) + "</h3>");
        document.write("<h3>thresholdCopy(3): " 
                + thresholdCopy(3) + "</h3></div>");
    

  

输出：