How can I selectively colour histogram bars in R? - r

Question

I did 10,000 stochastic implementations of a model, and want to plot some outputs. Long story short, the plot shows how long two species co-occurred within the system on a given run. Here's an example:
Now, I want to colour the histogram bars to specify which species lasted longer within the system. Specifically, I want to be able to specify if Species A outlasted Species B, if Species B outlasted Species A, or if both species went "extinct" at the same time, within a given simulation.
So, I made three vectors containing the run numbers (out of 10,000) for each of these three outcomes. For example:
# Pi wins
PiWins_1 <- which(Winner_1[1:10000, 2] %in% TRUE)
head(PiWins_1)
# [1] 1 2 6 7 9 12
# Pj wins
PjWins_1 <- which(Winner_1[1:10000, 3] %in% TRUE)
head(PjWins_1)
# [1] 3 4 5 8 10 11
# Ties
Ties_1 <- which(Winner_1[1:10000, 4] %in% TRUE)
head(Ties_1)
# [1] 20 24 29 40 110 132
And am now trying to figure out how to use these (or some other method) to colour each of the 10,000 histogram bars accordingly?
This is the ggplot script so far:
Histogram_1 <- ggplot(temp_df_1, aes(x=persistance_vec_1))+
geom_histogram(binwidth = 1, fill = "darkseagreen2")+
geom_vline(aes(xintercept = mean_pv_1, colour = "Mean # of Overlapping Time Pts in Stoch Runs"))+
geom_vline(aes(xintercept = cmean_pv_1, colour = "Conditional Mean # of Overlapping Time Pts in Stoch Runs (Dashed)"), linetype=2)+
geom_vline(aes(xintercept = median_pv_1, colour = "Median # of Overlapping Time Pts in Stoch Runs"))+
geom_vline(aes(xintercept = cmedian_pv_1, colour = "Conditional Median # of Overlapping Time Pts in Stoch Runs (Dashed)"), linetype=2)+
geom_vline(aes(xintercept = DO_1, colour = "Overlap in Det Sim"))+
labs(title="Det vs Stoch Overlap; Intro # 1, 10000 sims",
x="# of Time Pts Pi and Pj Co-occur",
y="# of Sims")+
scale_colour_manual(name="Legend",
values=c("Mean # of Overlapping Time Pts in Stoch Runs" = "navyblue",
"Conditional Mean # of Overlapping Time Pts in Stoch Runs (Dashed)" = "navyblue",
"Median # of Overlapping Time Pts in Stoch Runs" = "red2",
"Conditional Median # of Overlapping Time Pts in Stoch Runs (Dashed)" = "red2",
"Overlap in Det Sim" = "orange"))+
theme_minimal()
Histogram_1
Please let me know if I should provide any more information! Thanks so much in advance for any suggestions :)

Answer 1

Okay so I think what you're asking for is just how to colour bars by different colours. Here's a reprex:
x = c(1:10)
y = c(11:15, 15:11)
z = sample(c("A", "B", "C"), 10, replace = TRUE)
df = data.frame(x = x, y = y, z = z)
And then the plot - you can just use the fill argument in geom_col() if you want to use ggplot.
library(ggplot2)
df$z = as.factor(df$z)
ggplot(data = df) +
geom_col(aes(x = x, y = y, fill = z), colour = "black")
Does this do what you're looking to do?
Or if you really want to use geom_histogram(), here's an option with a different reprex:
# make the numeric data
x = sample(c(1:10), 50, replace = TRUE)
# initialize empty vector for categorical variables
z = vector(mode = "character", length = 50)
# im making 3 groups that i've randomly decided to group
for(i in 1:length(x)){
z[i] = ifelse(x[i] %in% c(1,3,5,7,9), # if x is an odd number, z=A
"A",
ifelse(x[i] %in% c(2,4,6), # if x in (2,4,6), z=B, if not, z=C
"B", "C"))
}
#turn into dataframe
df = data.frame(x = x, z = z)
and then the plot using the same idea:
df$z = as.factor(df$z)
ggplot(data = df) +
geom_histogram(aes(x = x, fill = z), colour = "black")