d3过渡圈到json数据值

Question

I am trying to set up a force directed layout in d3 and have my nodes start with an initial radius at 0. I then want for the user to be able to press a button and have the radius of the nodes scale to a size in accordance with a json data value. When I try to do this however, I get a javascript error "Cannot read property 'FIELD4' of undefined.

Here is the json data: https://api.myjson.com/bins/2n7do

And here is the code:

 // Update nodes. circles = circles.data(data); circles.exit().remove(); var nodeEnter = circles.enter().append("g") .attr("class", "node") .style("fill", function(d) { return color(d.FIELD5); }) .style("opacity", 0.75) .call(force.drag); nodeEnter.append("circle") .attr("r", 9) d3.select(circles).transition() .delay(3000) .duration(1000) .attr("r", function(d) { return d.FIELD4 * 0.000195 });; 

Answer 1

circles is d3 selection. By doing d3.select(circles) you select selection. I don't think it's valid. Instead of d3.select(circles).transition() try circles.transition()