Question

我有一个像这样的JSON文件：

{  
   "directed":false,
   "graph":[  
      [  
         "node_default",
         {  

         }
      ],
      [  
         "name",
         "()_with_int_labels"
      ],
      [  
         "edge_default",
         {  

         }
      ]
   ],
   "nodes":[  
      {  
         "id":0,
         "Year":1996,
         "Venue":"SWAT",
         "cYear":1996,
         "label":"The randomized complexity of maintaining the minimum"
      },
      {  
         "id":1,
         "Year":1998,
         "Venue":"SWAT",
         "cYear":1998,
         "label":"Probabilistic data structures for priority queues"
      }
   ],
   "links":[  
      {  
         "Edge Id":"12640",
         "target":65,
         "source":0,
         "Year":2011
      },
      {  
         "Edge Id":"12714",
         "target":50,
         "source":0,
         "Year":1996
      }
   ],
   "multigraph":false
}

我希望从Year获取变量nodes的最大值，并首先在控制台日志中显示它，然后将其用作变量以进行进一步处理。

我做的是：

d3.json("swatwads.json", function(error, graph) {
  graphdata=graph;
  graphRec=JSON.parse(JSON.stringify(graph)); //Add this line

  // Node and Link habitual defitions

  console.log(d3.max(d3.values(graph.nodes, function(d) {return d.Year;} )));

  });

当我运行代码时，它会检索整个第一个nodes对象，而我想要的是Year对象的变量nodes的最大值。

我做错了什么？我该如何解决？

谢谢！

Answer 1

你只想要一行

OUTPUT

Working fiddle

因此，您只需要console.log(d3.max(graph.nodes, function(d) {return d.Year;} ));的{{1}}值max

完整示例

year

Answer 2

这样做你想要的吗？

d3.json("swatwads.json", function(error, graph) {
  var nodes = graph.nodes
  var max = 0
  for (var ii=0, node; node=nodes[ii]; ii++){
    if (node.Year > max) {
      max = node.Year
    }
  }
  console.log(max)
}

从JSON对象D3JS获取最大值

2 个答案: