facet_grid labeller two lines

Question

I would like to use the labeller argument (and function) in facet_grid from the ggplot2 package, so that multiple labels on one axis go under each other, rather than next to each other.

In the reproducible example below, I would like to get the label to say the company name with the sector underneath it in the same 'label box' i.e. 'ABC Ltd\nAAAAAAAA' and 'DEF plc\nAAAAAAAA' and 'GHI LLP\nBBBBBBBBB' for the y axis facet labels. Ideally I would like to extend this for multiple additional label descriptions that go underneath.

require(ggplot2)
require(reshape2)
require(dplyr)

dat <- data.frame(date=Sys.Date()+seq(1000),
                  stock_px_1=100*cumprod(c(1,1+rnorm(999,0.00003,0.0004))),
                  stock_px_2=500*cumprod(c(1,1+rnorm(999,0.00001,0.0003))),
                  stock_px_3=10*cumprod(c(1,1+rnorm(999,0.00005,0.0005))))

stock_info <- data.frame(px_name=paste0('stock_px_',seq(3)),
                         stock_id=c('a1b2c3','d4e5f6','g7h8i9'),
                         sector=c('AAAAAAAA','AAAAAAAA','BBBBBBBBB'),
                         long_name=c('ABC Ltd','DEF plc','GHI LLP'))


dat_melted <- melt(dat,id.vars='date',variable.name='px_name',value.name='price')

joined_dat <- left_join(dat_melted,stock_info,by='px_name')

ggplot(joined_dat,aes(x=date,y=price,color=px_name))+
  geom_path()+
  facet_grid(long_name+sector~.,scales='free_y')+
  theme(strip.text.y=element_text(angle=0))+
  theme(legend.position='none')

Haboryme Haboryme · Accepted Answer · 2017-01-24T12:17:53

One way could be to simply add a new column that holds the combined labels:

joined_dat$combinedlabel=paste0(joined_dat$long_name,"\n",joined_dat$sector)

And then use said column to facet:

ggplot(joined_dat,aes(x=date,y=price,color=px_name))+
  geom_path()+
  facet_grid(combinedlabel~.,scales='free_y')+
  theme(strip.text.y=element_text(angle=0))+
  theme(legend.position='none')

facet_grid labeller two lines

2 Answers