Question

How can I rotate axis labels in R

Answer 1

library(ggplot2)
p <- data.frame(Day=c("2011-04-11", "2014-05-24","2004-01-12","2014-06-20","2010-08-07","2014-05-28"), Impressions=c(24010,15959,16107,21792,24933,21634),Clicks=c(211,106,248,196,160,241))
p

         Day Impressions Clicks
1 2011-04-11       24010    211
2 2014-05-24       15959    106
3 2004-01-12       16107    248
4 2014-06-20       21792    196
5 2010-08-07       24933    160
6 2014-05-28       21634    241

p$Day <- strptime(p$Day,"%Y-%m-%d") #formatting into Date 
q <- ggplot(p, aes(x=Day,y=Clicks)) + geom_line()
q

q + theme(axis.text.x = element_text(angle = 60, hjust = 1))

Thus, you can rotate labels for both X and Y axis in the similar way.