CODEWITHSUNDEEP
rggplot2expressiongeom-text
ginn
ginn

Reputation: 151

Add geom_text with x bar and round values

I have a 6-facet ggplot2 bar chart. I want each facet to be annotated with its respective mean value. Like this:

x̄ = 0.25

So I have been trying:

geom_text (data = averages, inherit.aes = FALSE,
           aes (label = expression (bar (x) == round (Mean, 2)), x = 30, y = 61.5)) +

But I always get this in return:

Don't know how to automatically pick scale for object of type <expression>. Defaulting to continuous.
Error in `geom_text()`:
! Problem while computing aesthetics.
ℹ Error occurred in the 2nd layer.
Caused by error in `compute_aesthetics()`:
! Aesthetics are not valid data columns.
✖ The following aesthetics are invalid:
✖ `label = expression(bar(x) == round(Mean, 2))`
ℹ Did you mistype the name of a data column or forget to add `after_stat()`?
Run `rlang::last_trace()` to see where the error occurred.

I've also tried most suggestions from these two posts: Combining paste() and expression() functions in plot labels and Putting mathematical symbols and subscripts mixed with regular letters

Is there any way to do this?

Upvotes: 2

Views: 54

Answers (1)

stefan
stefan

Reputation: 125418

One option would be to use paste(0) with parse=TRUE like so:

averages <- data.frame(
  facet = letters[1:6],
  Mean = 1:6
)

library(ggplot2)

ggplot() +
  geom_text(
    data = averages, inherit.aes = FALSE,
    aes(label = paste0("bar(x) == ", round(Mean, 2)), x = 30, y = 61.5),
    parse = TRUE
  ) +
  facet_wrap(~facet)

Upvotes: 3

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