CODEWITHSUNDEEP
rggplot2
Jake Fisher
Jake Fisher

Reputation: 3310

Why does my ggplot2 bar chart not display with a ylim minimum that is greater than 0?

I'm trying to plot answers on a scale from 1 to 5, and I would like my plot in ggplot2 to range from 1 to 5. When I change scale_y_continuous(limits = c(1, 5)), however, the data disappear. Any ideas how to fix this (other than the hack-y way of subtracting 1 from my values and relabeling)?

Reproducible example:

dat <- structure(list(year = structure(c(1L, 2L, 3L, 4L, 1L, 2L, 3L, 
4L, 1L, 2L, 3L, 4L, 1L, 2L, 3L, 4L, 1L, 2L, 3L, 4L, 1L, 2L, 3L, 
4L, 1L, 2L, 3L, 4L), .Label = c("2011", "2012", "2013", "2015"
), class = "factor"), variable = structure(c(1L, 1L, 1L, 1L, 
2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 
6L, 6L, 6L, 6L, 7L, 7L, 7L, 7L), .Label = c("instructor.knowledge", 
"instructor.enthusiastic", "instructor.clear", "instructor.prepared", 
"instructor.feedback", "instructor.out.of.class", "class.dynamic"
), class = "factor"), value = c(5, 4.75, 5, 4.75, 5, 5, 4.85714285714286, 
4.75, 4.75, 4.75, 4.71428571428571, 3.75, 5, 4.75, 5, 4.5, 5, 
4.75, NA, 5, 5, 5, NA, 4.5, 5, 5, NA, 4.5)), row.names = c(NA, 
-28L), .Names = c("year", "variable", "value"), class = "data.frame")

library(ggplot2)
ggplot(dat, aes(x = variable, y = value, fill = year)) + 
  geom_bar(position = "dodge", stat = "identity") +
  scale_y_continuous(name = "Average score across all respondents",
                     limits = c(1, 5),  # fails
                     # limits = c(0, 5),  # succeeds
                     breaks = 1:5)

Upvotes: 2

Views: 590

Answers (2)

eipi10
eipi10

Reputation: 93811

Just as another option, your data might be easier to understand as a faceted line plot:

ggplot(dat, aes(x = year, y = value, group=1)) + 
  geom_point() +
  geom_line() +
  scale_y_continuous(name = "Average score across all respondents",
                     limits = c(1, 5),  # fails
                     # limits = c(0, 5),  # succeeds
                     breaks = 1:5) +
  facet_grid(. ~ variable)

enter image description here

Upvotes: 3

LyzandeR
LyzandeR

Reputation: 37879

You just need to set the oob = rescale_none argument and it will work:

library(scales)
library(ggplot2)
ggplot(dat, aes(x = variable, y = value, fill = year)) + 
  geom_bar(position = "dodge", stat = "identity") +
  scale_y_continuous(name = "Average score across all respondents",
                     limits = c(1, 5),
                     oob = rescale_none)

enter image description here

Make sure to attach the scales package for the oob = rescale_none to work.

Upvotes: 4

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