<分区>
我想根据域为散点图中的点着色,但出现错误:Uncaught TypeError: d3.scaleOrdinal is not a function
var colors = ["#63b598", "#ce7d78", "#ea9e70"];
var color = d3.scaleOrdinal().domain(['a','b','c']).range(colors);
svg.selectAll(".dot")
.data(data)
.enter().append("circle")
.attr("class", "dot")
.attr("r", 3.5)
.attr("cx", xMap)
.attr("cy", yMap)
.style("fill", function(d){ return color(d.category)})