d3.js，我想添加數據值在json

Question

我正在使用d3.js。 創建並希望在文件json中創建總能量值。 我應該使用nest（）函數嗎？

[ 
{"name":"a","energy":200}, 
{"name":"b","energy":400}, 
{"name":"c","energy":450}, 
{"name":"d","energy":300}, 
{"name":"e","energy":120} 
] 

Answer 1

您的問題不清楚。我想你想添加一個新的屬性與總到每個對象......在這種情況下，使用forEach：

var data = [ 
 
{"name":"a","energy":200}, 
 
{"name":"b","energy":400}, 
 
{"name":"c","energy":450}, 
 
{"name":"d","energy":300}, 
 
{"name":"e","energy":120} 
 
]; 
 

 
var total = d3.sum(data, d=> d.energy); 
 

 
data.forEach(d => { 
 
d.total = total; 
 
}); 
 

 
console.log(data);

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>