ggplot boxplot not plotting when supplying breaks - r

Question

I have 7 values that I am trying to plot using geom_boxpot and I wish to only show certain values in the legend so am using the breaks argument in the scale_linetype_manual function but it doesn't plot those boxplots at all,
Boxplot using scale_linetype_manual
However, if I use the same code with scale_linetype_discrete it works fine and plots and only gives me the required values in the legend. But, I can't control the linetype in the function using the values argument. Is there a way to add values to the scale_linetype_discrete function?
Boxplot using scale_linetype_discrete
EDIT - UPDATED with fake data + code
> head(debug)
# A tibble: 6 × 4
subj time cond y
<dbl> <chr> <chr> <dbl>
1 1 one one_A 2
2 1 two two_A 1
3 1 two two_B 5
4 1 two two_C 0
5 1 three three_A 4
6 1 four four_A 4
> dput(debug)
structure(list(subj = c(1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4), time = c("one",
"two", "two", "two", "three", "four", "four", "one", "two", "two",
"two", "three", "four", "four", "one", "two", "two", "two", "three",
"four", "four", "one", "two", "two", "two", "three", "four",
"four"), cond = c("one_A", "two_A", "two_B", "two_C", "three_A",
"four_A", "four_B", "one_A", "two_A", "two_B", "two_C", "three_A",
"four_A", "four_B", "one_A", "two_A", "two_B", "two_C", "three_A",
"four_A", "four_B", "one_A", "two_A", "two_B", "two_C", "three_A",
"four_A", "four_B"), y = c(2, 1, 5, 0, 4, 4, 2, 2, 4, 3, 0, 1,
5, 3, 1, 5, 4, 2, 0, 4, 4, 0, 0, 4, 2, 1, 5, 5)), row.names = c(NA,
-28L), spec = structure(list(cols = list(subj = structure(list(), class = c("collector_double",
"collector")), time = structure(list(), class = c("collector_character",
"collector")), cond = structure(list(), class = c("collector_character",
"collector")), y = structure(list(), class = c("collector_double",
"collector"))), default = structure(list(), class = c("collector_guess",
"collector")), delim = ","), class = "col_spec"), problems = <pointer: 0x600004737380>, class = c("spec_tbl_df",
"tbl_df", "tbl", "data.frame"))
# Scale_linetype_discrete (would like to add linetype values to this)
ggplot() +
geom_boxplot(debug,
mapping = aes(x = time,
y = y,
linetype = cond),
show.legend = TRUE) +
scale_x_discrete(limits = c("one","two","three","four"),
labels = c("one","two","three","four")) +
scale_linetype_discrete(name = "My legend",
breaks = c("two_A","two_B","two_C","four_A","four_B"),
labels = c("two_A","two_B","two_C","four_A","four_B"))
# Scale_linetype_manual (would like 'one' and 'three' to be actually plotted but not showing in my legend)
ggplot() +
geom_boxplot(debug,
mapping = aes(x = time,
y = y,
linetype = cond),
show.legend = TRUE) +
scale_x_discrete(limits = c("one","two","three","four"),
labels = c("one","two","three","four")) +
scale_linetype_manual(name = "My legend",
breaks = c("two_A","two_B","two_C","four_A","four_B"),
labels = c("two_A","two_B","two_C","four_A","four_B"),
values = c("solid","dashed","solid","dashed","solid", "dashed","solid"))

Answer 1

Not sure about the reasons why your code does not work. But one option to fix your issue would be to make use of a named vector to assign linetypes to categories of you cond variable:
library(ggplot2)
lty <- c("solid", "dashed", "solid", "dashed", "solid", "dashed", "solid")
names(lty) <- c("four_A", "four_B", "one_A", "three_A", "two_A", "two_B", "two_C")
ggplot() +
geom_boxplot(debug,
mapping = aes(
x = time,
y = y,
linetype = cond
)
) +
scale_x_discrete(
limits = c("one", "two", "three", "four"),
labels = c("one", "two", "three", "four")
) +
scale_linetype_manual(
name = "My legend",
breaks = c("two_A", "two_B", "two_C", "four_A", "four_B"),
values = lty
)