Susannalsy
x <- rep(c("a", "b", "c"), each = 10)
y <- rep(1:30)
z <- rnorm(30)
plot(y, z, col = as.factor(x), pch = 19)
#如果想指定颜色
plot(y, z, col = c("blue", "purple", "pink")[as.factor(x)], pch = 19)
<sup>Created on 2020-11-17 by the reprex package (v0.3.0)</sup>