Update selection not working

Question

I\'m new to D3 and I am trying to display a simple d3 bar chart that changes which data attribute it is visualizing based on a dropdown menu - the data remains the same and I am

Answer 1

Actually, you don't have an update selection in your code.

For having an update selection, break up your "enter" selection, like this:

//this is the update selection
var bars = g.selectAll(".bar")
    .data(data, function(d) {
        return d._id;
    });

//and the remainder is the enter selection
bars.enter().append("rect")
    .attr("class", "bar")
    .attr("height", 0)
    .attr("y", height);

Also, it's worth mentioning that, since you don't have an update selection in your code, this...

bars.exit().remove();

... is useless.