 <p>This should do the trick:</p> <pre><code>d3.csv("wlythree.csv", function(data) { var values = []; values = data.map(function(d) { return d.percentage; }); console.log(values) }); </code></pre> <p>It yields:</p> <pre><code>["0.275862068965517", "0.137931034482759", ...] </code></pre> <p>EDIT: placed declaration of <code>values</code> inside the callback since the csv loading is asynchronous and that better reflects the script flow.</p>