CODEWITHSUNDEEP
rggplot2
Fspluver
Fspluver

Reputation: 21

Trouble using facet_wrap

I'm a newbie, so this might be super basic. When I run this code

Dplot <- qplot(x = diamonds$carat, y = diamonds$price, color = diamonds$color) +
  ggtitle("An A+ plot") +
  xlab("carat") +
  ylab("price") +
  geom_point()

Dplot <- Dplot + facet_wrap(vars(diamonds$clarity))
Dplot

I get an error message that says:

Error in gList(list(x = 0.5, y = 0.5, width = 1, height = 1, just = "centre", : only 'grobs' allowed in "gList"

I've tried googling, but haven't been able to figure out what the issue is.

Upvotes: 1

Views: 310

Answers (1)

Gregor Thomas
Gregor Thomas

Reputation: 146110

I would advise against using qplot except in the most basic cases. It teaches bad habits (like using $) that should be avoided in ggplot.

We can make the switch by passing the data frame diamonds to ggplot(), and putting the mappings inside aes() with just column names, not diamonds$. Then the facet_wrap works fine as long as we also omit the diamonds$:

Dplot = ggplot(diamonds, aes(x = carat, y = price, color = color)) +
  ggtitle("An A+ plot") +
  xlab("carat") +
  ylab("price") +
  geom_point()

Dplot + facet_wrap(vars(clarity))

Dplot + facet_wrap(~ clarity) # another option

Notice the code is actually shorter because we don't need to type diamonds$ all the time!

The vars(clarity) option works fine, more traditionally you would see formula interface used ~ clarity. The vars() option is new-ish, and will play a little nicer if you are writing a function where the name of a column to facet by is stored in a variable.

Upvotes: 3

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