Question

I have a very simple D3 example that first reads data into an associative array, then displays it in a bar graph.

I can’t seem to get anything to display using this method though. Instead, I have to insert a task in between: Read the data into an associative array, copy that data into a simple array, then display the bar graph using the simple array.

chart.selectAll("div")
     .data(genreAssociative)
     .enter().append("div")
     .style("width", function(d) { return d * 10 + "px"; })
     .text(function(d) { return d; });

The above does not work.

genreSimple = [];
for (var genre in genreAssociative) genreSimple.push(genreAssociative[genre]);         
chart.selectAll("div")
     .data(genreSimple)
     .enter().append("div")
     .style("width", function(d) { return d * 10 + "px"; })
     .text(function(d) { return d; });

The above does; using a simple array as an intermediary. Is there a special way to iterate over an associative array instead of a standard array?

Answer 1

You can use the functions d3.values or d3.entries to work directly with associative arrays. You simply need to take it into account in the functions that set attributes (e.g. function(d) { return d.value; }).