我们如何使用D3JS获取嵌套的json数组值

Question

我是D3JS的新手，尝试使用嵌套的json数组来显示条形图.Below是我的json。

[  
   {  
      "image":"suresh.jpg",
      "name":"Suresh",
      "email":"abc@gmail.com",
      "barValues":[  
         {  
            "letter":"A",
            "frequency":".04253"
         },
         {  
            "letter":"B",
            "frequency":".12702"
         },
         {  
            "letter":"C",
            "frequency":".02288"
         }
      ]
   }
]

以下是我的D3代码。

     $scope.showDetails = function(relatedData) {
            $http.get("searchInfo.json").success(function(response) {
                var x = response;
                $scope.data = [];
                 var searchT = relatedData;
                var margin ={top:20, right:30, bottom:30, left:20},
                    width=360-margin.left- margin.right,
                    height=200-margin.top-margin.bottom;

        var x = d3.scale.ordinal().rangeRoundBands([0, width], .1);
        var y = d3.scale.linear().range([height, 0]);
        var chart = d3.select("#chart")
                    .append("svg")
                      .attr("width", 600)
                      .attr("height", height+margin.top+margin.bottom);
        var xAxis = d3.svg.axis()
                      .scale(x)
                      .orient("bottom");

        var yAxis = d3.svg.axis()
                      .scale(y)
                      .orient("left");

        d3.json(searchT+'Details.json', function(error, data){
          x.domain(data.map(function(d){ return d.letter}));
          y.domain([0, d3.max(data, function(d){return d.frequency})]);

          var bar = chart.selectAll("g")
                            .data(data)
                          .enter()
                            .append("g")
                            .attr("transform", function(d, i){
                              return "translate("+x(d.letter)+", 0)";
                            });

          bar.append("rect")
              .attr("y", function(d) {
                return margin.top+margin.right; 
              })
              .attr("x", function(d,i){
                return x.rangeBand()+(margin.left/4);
              })
              .attr("height", function(d) {
                return height - y(d.frequency); 
              })
              .attr("width", 29);

          bar.append("text")
              .attr("x", x.rangeBand()+margin.left )
              .attr("y", function(d) { return y(d.frequency) -10; })
              .attr("dy", ".75em")
              .text(function(d) { return d.frequency; });

          chart.append("g")
                .attr("class", "x axis")
                .attr("transform", "translate("+margin.left+","+ height+")")        
                .call(xAxis);

          chart.append("g")
                .attr("class", "y axis")
                .attr("transform", "translate("+margin.left+",0)")
                .call(yAxis)
                .append("text")
                .attr("transform", "rotate(-90)")
                .attr("y", 6)
                .attr("dy", ".71em")
                .style("text-anchor", "end")
                .text("Frequency");
        });

         });
    };
}

我无法获得X轴和Y轴值。我尝试过不同的方式，但没有工作。可以帮助我，谢谢。