creating elements

But what if we had four numbers to display, rather than three? We wouldn’t have enough circles to display all the numbers. When joining data to elements, D3 stores the leftover data in the enter selection. (The terms enter and exit are adopted from stage terminology.) Here, the fourth number 293 remains in the enter selection, because we only have three circle elements:

var circle = svg.selectAll("circle")
      .data([32, 57, 112, 293]);