CODEWITHSUNDEEP
rggplot2
GTK
GTK

Reputation: 133

How can I use ggplot2 and stat_bin to make a bar chart that includes numeric levels with no observations

I have data as an ordered factor, with levels 1,2,3,4,5. (This is Likert scale data.) I would like to use ggplot to create a bar chart of counts, but this must include all the levels, even the ones with zero count. Here is an example data frame with zero count at the level equal to 2.

library(ggplot2)

foo <- structure(list(feed.n.1.50..3. = structure(c(4L, 4L, 4L, 4L, 
4L, 5L, 5L, 4L, 1L, 1L,1L, 1L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
4L, 4L, 4L, 4L, 4L, 5L, 5L, 4L, 5L, 4L, 4L, 4L, 4L, 4L, 4L, 4L, 
5L, 3L, 4L, 4L, 3L, 4L, 4L, 3L, 4L, 5L, 4L, 4L, 4L, 4L), .Label = c("1", 
"2", "3", "4", "5"), class = c("ordered", "factor"))), .Names = "answers", row.names = c(NA, 
-50L), class = "data.frame")

table(foo) # satisfy myself the level 2 has zero entries

ggplot(foo,aes(answers)) + geom_bar(stat="bin") # stat="bin" is not needed, but there for clarity

stat_bin() has a parameter drop, documented as

drop: If TRUE, remove all bins with zero counts

The default is FALSE, though, so I expected the levels to be kept. Is there a simple way to use ggplot to keep all the levels of the factor?

Upvotes: 3

Views: 408

Answers (1)

Didzis Elferts
Didzis Elferts

Reputation: 98429

Dropping of level is done by scales (default), so use scale_x_discrete() with argument drop=FALSE to show all levels.

ggplot(foo,aes(answers)) + geom_bar()+
  scale_x_discrete(drop=FALSE)

enter image description here

Upvotes: 6

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