for loop issue in ggplot2 - r

Question

I would like to output multiple graphs from ggplot2. I found very nice examples but still could not find what I want to achieve.
r-saving-multiple-ggplots-using-a-for-loop
by using similar example, I only want to output three different graphs for each species so far I am outputting same three combined graph.
library(dplyr)
fill <- iris%>%
distinct(Species,.keep_all=TRUE)
plot_list = list()
for (i in 1:length(unique(iris$Species))) {
p = ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width)) +
geom_point(size=3, aes(colour=Species))
geom_rect(data=fill,aes(fill = Petal.Width),xmin = -Inf,xmax = Inf,ymin = -Inf,ymax = Inf,alpha = 0.5)+ ## added later to OP
plot_list[[i]] = p
}
# Save plots to tiff. Makes a separate file for each plot.
for (i in 1:3) {
file_name = paste("iris_plot_", i, ".tiff", sep="")
tiff(file_name)
print(plot_list[[i]])
dev.off()
}
What I am missing?

Answer 1

You are not filtering the dataset inside the for-loop, and so the same graph is repeated three times without change.
Note the changes here:
plot_list = list()
for (i in unique(iris$Species)) {
p = ggplot(iris[iris$Species == i, ], aes(x=Sepal.Length, y=Sepal.Width)) +
geom_point(size=3, aes(colour=Species))
plot_list[[i]] = p
}
Addressing the OP update, this works for me:
fill <- iris %>%
distinct(Species, .keep_all=TRUE)
for (i in unique(iris$Species)) {
p = ggplot(iris[iris$Species == i, ], aes(x=Sepal.Length, y=Sepal.Width)) +
geom_rect(data = fill, aes(fill = Petal.Width),xmin = -Inf,xmax = Inf,ymin = -Inf,ymax = Inf,alpha = 0.5) +
geom_point(size = 3, aes(colour = Species))
plot_list[[i]] = p
}