Can't label multi-panel figure in r while using ggplot

Question

Sorry for the possibly simple question. I\'m a programmer, though I rarely deal with graphics, and after tearing my hair out for hours with this problem, it\'s time to get some

Answer 1

You could use ggtitle and theme:

df = data.frame(gp = factor(rep(letters[1:3], each = 10)), y = rnorm(30))
p = ggplot(df) + geom_point(aes(x = gp, y = y)) + ggtitle('a') + theme(plot.title=element_text(hjust=0))
p2 = ggplot(df) + geom_point(aes(x = y, y = gp)) + ggtitle('b') + theme(plot.title=element_text(hjust=0))
grid.arrange(p, p2, ncol = 2)