Question

将CSV转换为JSON时遇到困难.Below是我要转换的代码

d3.csv("http://localhost:8080/Sample/flight.csv", function(flights) {           
                //alert(flights);
              var linksByOrigin = {},
                  countByAirport = {},
                  locationByAirport = {},
                  positions = [];

              var arc = d3.geo.greatArc()
              .source(function(d) { return locationByAirport[d.source]; })
              .target(function(d) { return locationByAirport[d.target]; }); 

              //reading from csv
                flights.forEach(function(flight) {
                var origin = flight.origin,
                    destination = flight.destination,
                    links = linksByOrigin[origin] || (linksByOrigin[origin] = []);
                links.push({source: origin, target: destination});
                countByAirport[origin] = (countByAirport[origin] || 0) + 1;
                countByAirport[destination] = (countByAirport[destination] || 0) + 1;
              });

}）;

到

d3.json("http://localhost:8080/Sample/flight.json", function(flights) {             
                //alert(flights);
              var linksByOrigin = {},
                  countByAirport = {},
                  locationByAirport = {},
                  positions = [];

              var arc = d3.geo.greatArc()
              .source(function(d) { return locationByAirport[d.source]; })
              .target(function(d) { return locationByAirport[d.target]; }); 

              var flights = flights.flights;
              alert("flights"+flights.length);
           for(var i = 0; i < flights.length; i++)    {    
               alert("origin"+flights[i].origin+"dest"+flights[i].destination);
                 var origin = flights[i].origin;
            var  destination = flights[i].destination;
          alert("origin"+origin+"dest"+destination)
                var links = linksByOrigin[origin] || (linksByOrigin[origin] = []);
                links.push({source: origin , target: destination});
                countByAirport[origin] = (countByAirport[origin] || 0) + 1;
                countByAirport[destination] = (countByAirport[destination] || 0) + 1;   
           }
});

当我使用json代码时，它正在给我19:15:41.950 TypeError: _ is undefined1 d3.v2.js:1982:10。请告诉我在转换时我做错了什么。

Answer 1

我需要查看你的json对象以获取更多信息，但基于以下假设，你的csv返回了一个对象数组：

[{origin: 'origin string', destination: 'destination string'} ... ]

如果您的json存储如下：

{flights: [{origin: 'origin string', destination: 'destination string'}, ...]}

那么你的代码应该可行。如果您的json格式不同，如果您可以上传示例csv和json文件，我可以给您更好的答案。

很难说这个错误有什么问题，但我的猜测是你没有在你的json文件中设置一个航班变量。

在d3.js中从CSV转换为JSON

1 个答案: