D3 Library — How To Access Data from JSON in this example

Question

I didn't explain the issue properly in the title... Sorry.

I'm following the D3 Tag Cloud Simple example https://github.com/jasondavies/d3-cloud/blob/master/examples/simple.html

I have a JSON file that consists of tweet tags, sentimental values and tweet text; (excerpt)

var words = [{"word":"disgrace","sentiment":"0.975","tweet":"Wheres Fred the weatherman? \nIn jail #disgrace #dirtyman @MrJimmyCorkhill"},{"word":"dirtyman","sentiment":"0.975","tweet":"Wheres Fred the weatherman? \nIn jail #disgrace #dirtyman @MrJimmyCorkhill"}];

I want to use the "tweet" value as a 'title' element of each 'text' element. I tried doing this by putting my tweet in the .words function (or .map, I don't know :s), as other data is accessed that way, but I can't extract my 'tweet' data;

var fill = d3.scale.category20();
var words = <?php echo $tweets->getTweetTags(); ?>;

d3.layout.cloud().size([1000, 1000])
.words(words.map(function(d) {
return {text: d.word, size: d.sentiment * 40, tweet: d.tweet};
}))
.rotate(function() { return ~~(Math.random() * 2) * Math.random() * 1; })
.font("Impact")
.fontSize(function(d) { return d.size; })
.on("end", draw)
.start();

function draw(words) {
d3.select("#vis").append("svg")
.attr("width", 1000)
.attr("height", 1000)
.append("g")
.attr("transform", "translate(500,400)")
.selectAll("text")
.data(words)
.enter().append("text")
.style("font-size", function(d) { return d.size + "px"; })
.style("font-family", "Impact")
.style("fill", function(d, i) { return fill(i); })
.attr("text-anchor", "middle")
.attr("transform", function(d) {
return "translate(" + [d.x, d.y] + ")rotate(" + d.rotate + ")";
})
.text(function(d) { return d.text; })
.append("svg:title").text(function(d) { return d.tweet; } );
}

d.tweet returns undefined

I can probably understand why I can't use my tweet in the .words or .map function, as they only expect certain parameters, but I don't know how else to get the 'tweet' data into the 'title' tags of each 'text' element.

Can anyone help me with this?

Edit: Code with inside d3.json function;

var data; // a global
            d3.json("../../../assets/json/tweetTags.json", function(error, json) {
              if (error) return console.warn(error);
              data = json;

              var fill = d3.scale.category20();

              d3.layout.cloud().size([1000, 1000])
                  .words(data.map(function(d) {
                    return {text: d.word, size: d.sentiment * 40, tweet: d.tweet};
                  }))
                  .rotate(function() { return ~~(Math.random() * 2) * Math.random() * 1; })
                  .font("Impact")
                  .fontSize(function(d) { return d.size; })
                  .on("end", draw)
                  .start();

              function draw(data) {
                d3.select("#vis").append("svg")
                    .attr("width", 1000)
                    .attr("height", 1000)
                  .append("g")
                    .attr("transform", "translate(500,400)")
                  .selectAll("text")
                    .data(words)
                  .enter().append("text")
                    .style("font-size", function(d) { return d.size + "px"; })
                    .style("font-family", "Impact")
                    .style("fill", function(d, i) { return fill(i); })
                    .attr("text-anchor", "middle")
                    .attr("transform", function(d) {
                      return "translate(" + [d.x, d.y] + ")rotate(" + d.rotate + ")";
                    })
                    .text(function(d) { return d.text; })
                    .append("svg:title").text(function(d) { return d.tweet; } );
              }

              d3.layout.cloud().size([300, 300])
              .data.map(function(d) {
                return {text: d, size: 10 + Math.random() * 90};
              })
              .rotate(function() { return ~~(Math.random() * 2) * 90; })
              .font("Impact")
              .fontSize(function(d) { return d.size; })
              .on("end", draw)
              .start();
            });

I don't know how to get it working in like that. I have made the json file but now I can't access the data or run the cloud.

Edit: The text elements are appending outside of the closing body tag now :(

var data; // a global
            d3.json("../../../assets/json/tweetTags.json", function(error, json) {
              if (error) return console.warn(error);
              data = json;

              var fill = d3.scale.category20();

             d3.select("#vis").append("svg")
                 .attr("width", 1000)
                 .attr("height", 1000)
                 .append("g")
                 .attr("transform", "translate(500,400)")
                 .data(json)
                 .enter().append("text")
                 .style("font-size", function(d) { return d.sentiment * 40 + "px"; })
                 .style("font-family", "Impact")
                 .style("fill", function(d, i) { return fill(i); })

                 .text(function(d) {return d.word;})
                 .append("svg:title").text(function(d) { return d.tweet; } );

            });

Edit: @Chris This is your exampled code in the D3 json function and with my customisations

d3.json("../../../assets/json/tweetTags.json", function(error, json) {
  if (error) return console.warn(error);

  var fill = d3.scale.category20();

  d3.layout.cloud().size([600, 500])
      .words(json.map(function(d) {;
            return {text: d.word, size: d.sentiment * 40, tweet: d.tweet};
       }))
      .rotate(function(d) { return ~~(Math.random() * 2) * 90; })
      .font("Impact")
      .fontSize(function(d) { return d.size; })
      .on("end", draw)
      .start();

  function draw(words) { 
      d3.select("body").append("svg")
          .attr("width", 600).attr("height", 500)
          .append("g").attr("transform", "translate(350,350)")
          .selectAll("text").data(words)
          .enter().append("text")
          .style("font-size", function(d) { return d.size + "px"; })
          .style("font-family", "Impact")
          .style("fill", function(d, i) { return fill(i); })
          .attr("text-anchor", "middle")
          .attr("transform", function(d) {
              return "translate(" + [d.x, d.y] + ")rotate(" + d.rotate + ")";
          })
          .text(function(d) { return d.text; }).append("svg:title")
          .text(function(d) { return d.tweet; } );
      }
})

But I can't access d.tweet from the draw function :s

Answer 1

I suggest you should use the built-in import function for json instead of php. I think that the problem you have is that the reading of the data is asynchronous, so words is not filled before using it in clouds.

The principle behind d3.json() is to do everything in this function, which will be executed when the json is loaded:

var data; // a global
d3.json("path/to/file.json", function(error, json) {
  if (error) return console.warn(error);
  data = json;
  visualizeit();
});

EDIT

Here is an example of the code that should work, I just added the d3 cloud example inside the json function.

d3.json("../../../assets/json/tweetTags.json", function(error, json) {
  if (error) return console.warn(error);

  var fill = d3.scale.category20();

  d3.layout.cloud().size([300, 300])    
      .words([  // To be replaced with data
        "Hello", "world", "normally", "you", "want", "more", "words",
        "than", "this"].map(function(d) {
            return {text: d, size: 10 + Math.random() * 90};
       }))
      .rotate(function() { return ~~(Math.random() * 2) * 90; })
      .font("Impact")
      .fontSize(function(d) { return d.size; })
      .on("end", draw)
      .start();

  function draw(words) {
      d3.select("body").append("svg")
          .attr("width", 300).attr("height", 300)
          .append("g").attr("transform", "translate(150,150)")
          .selectAll("text").data(words)
          .enter().append("text")
          .style("font-size", function(d) { return d.size + "px"; })
          .style("font-family", "Impact")
          .style("fill", function(d, i) { return fill(i); })
          .attr("text-anchor", "middle")
          .attr("transform", function(d) {
              return "translate(" + [d.x, d.y] + ")rotate(" + d.rotate + ")";
          })
          .text(function(d) { return d.text; });
      }
})

Then, when this version works you can just replace the .words() by:

.words(json.map(function(d) {
  return {text: d.word, size: d.sentiment * 40, tweet: d.tweet};
}))