在d3中检索数组的特定索引select

Question

以下选择数组连接中的所有元素。我只想要一个特定的。

var route = vis.selectAll("line.route") 
.data(connections) 
.enter().append("svg:line") 
    .attr("class", "route") 
    .attr("stroke", function(d) { return '#'+routesById[d.line].colour; }) 
    .attr("stroke-linecap", 'round') 
    .attr("x1", function(d) { return x(d.station1.longitude); }) 
    .attr("y1", function(d) { return y(d.station1.latitude); }) 
    .attr("x2", function(d) { return x(d.station2.longitude); }) 
    .attr("y2", function(d) { return y(d.station2.latitude); }) 

连接是一个数组（我想），在控制台上被定义为

[Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object, Object…] 

但是我只希望在一个特定的索引来选择一个元素。 我试图使用过滤器，但它没有工作？

.data(connections.filter(function(d) { return d[23] })) 

Answer 1

使用我

.data(connections.filter(function(d,i) { return i === 23; })) 

https://github.com/mbostock/d3/wiki/Selections#filter