ggplot: geom_dotplot, center the dots over multiple lines

Question

I have the following dotplot:

I want to achieve two things:

1. Instead of having the dots in a single row per facet, I want the dots to be lined across two rows (with 5 dots in the first row, and a further 5 dots in the second row), like this:

2. In each facet, the dotplots should be in the very center.

Is it possible to achieve this with geom_dotplot()? I would be grateful for your help!

My dataframe:

df <- tibble::tibble(
  has_twitter = c(0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 
    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1),
  Quartile = c("Q1", "Q1", "Q1", "Q1", "Q1", "Q1", "Q1", "Q1", "Q1", "Q1", 
    "Q2", "Q2", "Q2", "Q2", "Q2", "Q2", "Q2", "Q2", "Q2", "Q2", "Q3", 
    "Q3", "Q3", "Q3", "Q3", "Q3", "Q3", "Q3", "Q3", "Q3", "Q4", "Q4", 
    "Q4", "Q4", "Q4", "Q4", "Q4", "Q4", "Q4", "Q4")

My ggplot:

library(ggplot2)
ggplot(df, aes(x = Quartile, y = 1)) +
  geom_dotplot(binaxis="y",
               fill = factor(df$has_twitter),
               binwidth = 1,
               dotsize=0.2,
               stackdir="centerwhole") +
  theme(axis.title = element_blank(),
        axis.text = element_blank(),
        axis.ticks = element_blank()) +
  facet_wrap(~ Quartile, nrow = 4)

Answer 1

Is this a solution you are looking for?

library(tidyverse)

# data manipulation
df1 <- df %>% 
    mutate(group = ifelse(Quartile == "Q1" | Quartile == "Q2", "Q1_Q2", "Q3_Q4")) %>% 
    group_by(group) %>% 
    mutate(id = rep(row_number(), each=10, length.out = n()))

# plot
ggplot(df1, aes(x = 0.9, y = id)) +
    geom_dotplot(binaxis="y",
                 fill = factor(df$has_twitter),
                 binwidth = 1,
                 dotsize=0.2,
                 binpositions = "all") +
    theme(axis.title = element_blank(),
          axis.text = element_blank(),
          axis.ticks = element_blank()) +
    facet_wrap(~ group, nrow =2) +
    coord_cartesian(xlim = c(0.5, 1.5))