Question

I have a simplified dataframe

library(ggplot2)
df <- data.frame(wins=c(1,1,3,1,1,2,1,2,1,1,1,3))
ggplot(df,aes(x=wins))+geom_histogram(binwidth=0.5,fill="red")

I would like to get the final value in the sequence,3, shown with either a different fill or alpha. One way to identify its value is

tail(df,1)$wins

In addition, I would like to have the histogram bars shifted so that they are centered over the number. I tried unsuccesfully subtracting from the wins value

Answer 1

1) To draw bins in different colors you can use geom_histogram() for subsets.

2) To center bars along numbers on the x axis you can invoke scale_x_continuous(breaks=..., labels=...)

So, this code

library(ggplot2)
df <- data.frame(wins=c(1,1,3,1,1,2,11,2,11,15,1,1,3))
cond <- df$wins == tail(df,1)$wins

ggplot(df, aes(x=wins)) +
  geom_histogram(data=subset(df,cond==FALSE), binwidth=0.5, fill="red") +
  geom_histogram(data=subset(df,cond==TRUE), binwidth=0.5, fill="blue") +
  scale_x_continuous(breaks=df$wins+0.25, labels=df$wins)

produces the plot: