r - 如何在R中绘制三角形作为图例？

Question

我正在绘制一个需要绘制图例的情节，并且我需要其中一个是三角形。

  plot.new()
  legend(x=.5,y=.9, c("A","B","C","D"), cex=.8, bty="n", 
         fill = c("green","yellow","red","blue"))

我想legend D变成三角形。我该如何实施？

问候

Answer 1

使用pch和col（而不是fill）：

plot.new()
legend(x=.5,y=.9, c("A","B","C","D"), cex=.8, bty="n",
       col=c("green", "yellow", "red", "blue"), pch=c(15, 15, 15, 17))

Answer 2

pch 参数选择图例符号的形状：

     plot.new();

     legend(x=.5,y=.9, c("A","B","C","D"), 
            pch=c(1,4,3,2), cex=.8, bty="n",
            col=c("green","yellow","red","blue"))