r - Stagger axis labels, new feature in ggplot2

Question

Hi there: I need to plot a factor with 81 different categories with different frequency counts each. Each factor name is a 4-letter category. It looks like this. As you can see, it is pretty tough to read the factor labels. I'd like to stagger the y-axis according to this suggestion. However, this issue on github suggests that something has changed in ggplot2 and that the hjust and vjust options no longer work. Does anyone have any suggestions to make this plot look better, in particular to make the factor levels readable.

#libraries
# install.packages('stringi')
library(ggplot2)
library(stringi)
#fake data
var<-stri_rand_strings(81, 4, pattern='[HrhEgeIdiFtf]')
var1<-rnorm(81, mean=175, sd=75)
#data frame
out<-data.frame(var, var1)

#set levels for plotting
out$var<-factor(out$var, levels=out$var[order(out$var1, decreasing=FALSE)])
#PLot
out.plot<-out %>%
ggplot(., aes(x=var, y=var1))+geom_point()+coord_flip()
#Add staggered axis option
out.plot+theme(axis.text.y = element_text(hjust = grid::unit(c(-2, 0, 2),     "points")))

Answer 1

To stagger the labels, you could add spaces to the labels in the dataframe.

# Libraries
library(ggplot2)
library(stringi)

# fake data
set.seed(12345)
var <- stri_rand_strings(81, 4, pattern = '[HrhEgeIdiFtf]')
var1 <- rnorm(81, mean = 175, sd = 75)

out <- data.frame(var, var1)

# Add spacing, and set levels for plotting
out = out[order(out$var1), ]
out$var = paste0(out$var, c("", "       ", "            "))
out$var <- factor(out$var, levels = out$var[order(out$var1, decreasing = FALSE)])

# Plot
out.plot <- ggplot(out, aes(x = var, y = var1)) +
   geom_point() + coord_flip()
out.plot

Alternatively, draw the original plot, then edit. Here, I use the grid function, editGrob() to do the editing.

# Libraries
library(ggplot2)
library(gtable)
library(grid)
library(stringi)

# fake data
set.seed(12345)

var <- stri_rand_strings(81, 4, pattern = '[HrhEgeIdiFtf]')
var1 <- rnorm(81, mean = 175, sd = 75)

out <- data.frame(var, var1)

# Set levels for plotting
out$var <- factor(out$var, levels = out$var[order(out$var1, decreasing = FALSE)])

# Plot
out.plot <- ggplot(out, aes(x = var, y = var1)) +
   geom_point() + coord_flip()

# Get the ggplot grob
g = ggplotGrob(out.plot)

# Get a hierarchical list of component grobs
grid.ls(grid.force(g))

Look through the list to find the section referring to the left axis. The relevant bit is:

   axis-l.6-3-6-3   
     axis.line.y..zeroGrob.232   
     axis   
       axis.1-1-1-1   
         GRID.text.229   
       axis.1-2-1-2   

You will need to set up path from 'axis-l', through 'axis', through 'axis', though to 'GRID.text'.

# make the relevant column a little wider
g$widths[3] = unit(2.5, "cm")

# The edit
g = editGrob(grid.force(g), 
      gPath("axis-l", "axis", "axis", "GRID.text"), 
      x = unit(c(-1, 0, 1), "npc"), 
      grep = TRUE)

# Draw the plot
grid.newpage()
grid.draw(g)

Another option is to find your way through the structure to the relevant grob to make the edit.

# Get the grob
g <- ggplotGrob(out.plot)

# Get the y axis
index <- which(g$layout$name == "axis-l")  # Which grob
yaxis <- g$grobs[[index]]   

# Get the ticks (labels and marks)
ticks <- yaxis$children[[2]]

# Get the labels
ticksL <- ticks$grobs[[1]]

# Make the edit
ticksL$children[[1]]$x <- rep(unit.c(unit(c(1,0,-1),"npc")), 27)

# Put the edited labels back into the plot
ticks$grobs[[1]] <- ticksL
yaxis$children[[2]] <- ticks
g$grobs[[index]] <- yaxis

# Make the relevant column a little wider
g$widths[3] <- unit(2.5, "cm")

# Draw the plot
grid.newpage()
grid.draw(g)