R- split histogram according to factor level

Question

This is my data:

type<-rep(c(0,1),100) 
diff<-rnorm(100)
data<-data.frame(type,diff)

If I want to plot historgram of diff

Answer 1

That plot was made using the lattice package

set.seed(1)
type<-rep(c(0,1),100) 
diff<-rnorm(100)
data<-data.frame(type,diff)


library('lattice')
histogram(~ diff | type, data = data)

here is how you can do it in base graphics

## first plot - left half of x-axis, right margin set to 0 lines
par(fig = c(0, .5, 0, 1), mar = c(5,4,3,0))
hist(data$diff[data$type==0], ann = FALSE, las = 1)

## second plot - right half of x-axis, left margin set to 0 lines
par(fig = c(.5, 1, 0, 1), mar = c(5,0,3,2), new = TRUE)
hist(data$diff[data$type==1], ann = FALSE, axes = FALSE)
axis(1)
axis(2, lwd.ticks = 0, labels = FALSE)

title(main = 'Histogram', xlab = 'x label', outer = TRUE, line = -2)