How to display only integer values on an axis using ggplot2

This is what I use:

ggplot(data3, aes(x = factor(IR), y = value, fill = Legend, width = .15)) +
  geom_col(position = 'dodge', colour = 'black') + 
  scale_y_continuous(breaks = function(x) unique(floor(pretty(seq(0, (max(x) + 1) * 1.1)))))

With scale_y_continuous() and argument breaks= you can set the breaking points for y axis to integers you want to display.

ggplot(data2, aes(x =factor(IR), y = value, fill = Legend, width=.15)) +
    geom_bar(position='dodge', colour='black')+
    scale_y_continuous(breaks=c(1,3,7,10))

If you have the scales package, you can use pretty_breaks() without having to manually specify the breaks.

q + geom_bar(position='dodge', colour='black') + 
scale_y_continuous(breaks= pretty_breaks())