Julia: Gadfly画三条曲线，打上Label!

julia> using Gadfly;

julia> x = -12:12;

p1 = DataFrame(x=x, y=sin(x), label="sin");

p2 = DataFrame(x=x, y=cos(x), label="cos");

p3 = DataFrame(x=x, y=0.5*x, label="line");

p = vcat(p1, p2, p3);

mypl = Gadfly.plot(p, x="x", y="y", color="label", Geom.line,

         Scale.discrete_color_manual("blue","red", "green"))

Gadfly.draw(PNG("\\plot3.png", 6inch, 3inch), mypl)

然后，在“D:\\strategyJulia"目录下，找到mypl.png，文件，打开即可看到。