散点图子集颜色形状ifelse

Question

I'd like to do a scatter plot where some of the values, out of a subset, are plotted differently in colour and shape. I've worked around the following code but I don't manage to make it right. Any help greatly appreciated!

# My data
iris
iris$Code <- 1:150

# A selection of my data I'd like to plot differently
subset <- subset(iris, iris$Sepal.Width<3.5)
sel <- as.character(subset$Code) # I think the problems start here :)

# Plotting doesn't work
plot(iris$Sepal.Length ~ iris$Sepal.Width,
     col=ifelse(iris$Code==sel, "red", "black"),
     pch=ifelse(iris$Code==sel, 17, 1))

Answer 1

Try this:

#define subset
sel <- iris[iris$Sepal.Width<3.5,"Code"]
#plot
plot(iris$Sepal.Length ~ iris$Sepal.Width,
     col=ifelse(iris$Code %in% sel, "red", "black"),
     pch=ifelse(iris$Code %in% sel, 17, 1))

Note: in your code there are some obvious mistakes:

dd <- iris - why assign to dd and never use it?

iris$Sepal.Widith - spelling

... "black") - comma missing at the end.