R图中图例中的匹配颜色

Question

I'm just starting to use R and I'm trying to make a scatter plot which has different colors based on different attributes. For example:

data.a = 1:5
data.b = 1:5
data.c = c("yes", "no", "yes", "maybe", "no")
plot(data.a, data.b)

I want to have a legend which is different colors for points which are "yes", "no", and "maybe" for data.c. I would also like points to be the colors in the legend.

Answer 1

要详细说明@ MYaseen208的答案：对于图例（鉴于他的代码），您需要以下内容：

legend("topleft", legend=levels(factor(data.c)), text.col=seq_along(levels(factor(data.c))))

Answer 2

This seems like a good case for ggplot2 :

library("ggplot2")
data_df <- data.frame(a = data.a, b = data.b, c = data.c)
ggplot(data_df, aes(a,b)) + geom_point(aes(color=c))

Answer 3

试试这个

plot(data.a, data.b, col=factor(data.c))