Histogram with different colours using the abline function in R - r

Question

I would like to plot a histogram with different colours and legend.
Assuming the following data:
df1<- rnorm(300,60,5)
I have used the following codes to get the histogram plot and the lines using the abline function:
df1<-data.frame(df1)
attach(df1)
hist(M,at=seq(0,100, 2))
abline(v=80, col="blue")
abline(v=77, col="red")
abline(v=71, col="red")
abline(v=68, col="blue")
abline(v=63, col="blue")
abline(v=58, col="blue")
abline(v=54, col="blue")
abline(v=51, col="blue")
abline(v=457, col="blue")
Now I want to get the following plot. I wanted to remove the lines, but I was unable to do it. So I do not need to have the lines.

Answer 1

Here's one way of doing that with ggplot2, dplyr and tidyr.
First you need to set the colors. I do that with mutate and case_when. For the plot itself, it's important to remember that if histogram bins are not aligned, you can get different colors on the same bar. To avoid this, you can use binwidth=1.
library(ggplot2)
library(dplyr)
library(tidyr)
df1 <- data.frame(data1=rnorm(300,60,5))
df1 <- df1 %>%
mutate(color_name=case_when(data1<60 ~ "red",
data1>=60 & data1 <63 ~ "blue",
TRUE ~ "cyan"))
ggplot(df1,aes(x=data1, fill=color_name)) +
geom_histogram(binwidth = 1, boundary = 0, position="dodge") +
scale_fill_identity(guide = "legend")
Additional request in comment
Using case_when with four colors:
df1 <- data.frame(data1=rnorm(300,60,5))
df1 <- df1 %>%
mutate(color_name=case_when(data1<60 ~ "red",
data1>=60 & data1 <63 ~ "blue",
data1>=63 & data1 <65 ~ "orange",
TRUE ~ "cyan"))
ggplot(df1,aes(x=data1, fill=color_name)) +
geom_histogram(binwidth = 1, boundary = 0, position="dodge") +
scale_fill_identity(guide = "legend")