CODEWITHSUNDEEP
rggplot2dplyr
zach
zach

Reputation: 31003

applying a function to the output of dplyr's group_by

I would like to subset a large dataframe and create a ggplot of each grouping. Sounds like a perfect candidate for dplyr but I'm running into issues calling functions on the group_by results. Any hints would be greatly appreciated.

# what I want to do using base functions: "groupby" the elements in a column 
# and create/save a plot for each group
for (i in levels(iris$Species)){
  df = iris[iris$Species == i,]
  p <- ggplot(df, aes(x=Sepal.Length, y=Sepal.Width) + geom_point())
  ggsave(p, filename=paste(i,".pdf",sep=""))
}

# I'm trying to get something like this using dplyr
library(dplyr)
iris %>%
  group_by(Species) %>%
  do({
      p <- ggplot(., aes(x=Sepal.Length, y=Sepal.Width) + geom_point())
      ggsave(p, filename=paste(quote(Species),".pdf",sep=""))
     })

Upvotes: 3

Views: 1959

Answers (1)

MrFlick
MrFlick

Reputation: 206232

Well, you have a parenthesis problem and a file naming problem so maybe it's one of those that you are referring to. I'm assuming

iris %>%
  group_by(Species) %>%
  do({
      p <- ggplot(., aes(x=Sepal.Length, y=Sepal.Width)) + geom_point()
      ggsave(p, filename=paste0(unique(.$Species),".pdf"))
     })

would fix your problem.

Upvotes: 10

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