Left align two graph edges (ggplot)

Question

I\'m using ggplot and have two graphs that I want to display on top of each other. I used grid.arrange from gridExtra to stack them. The problem is I want the

Answer 1

Here is another possible solution using melt from the reshape2 package, and facet_wrap:

library(ggplot2)
library(reshape2)

dat = CO2[, c(1, 2)]
dat$id = seq(nrow(dat))
mdat = melt(dat, id.vars="id")

head(mdat)
#   id variable value
# 1  1    Plant   Qn1
# 2  2    Plant   Qn1
# 3  3    Plant   Qn1
# 4  4    Plant   Qn1
# 5  5    Plant   Qn1
# 6  6    Plant   Qn1

plot_1 = ggplot(mdat, aes(x=value)) + 
         geom_bar() + 
         coord_flip() +
         facet_wrap(~ variable, nrow=2, scales="free", drop=TRUE)

ggsave(plot=plot_1, filename="plot_1.png", height=4, width=6)