facet_cleaner.R

# Install these packages if you don't have them yet
# if (!require("pacman")) install.packages("pacman")
pacman::p_load(tidyverse, egg, gridExtra, grid, patchwork)


## Function to fix panel width and add "buffers" for right-alignment
## based on: https://gist.github.com/baptiste/eadeecd7d3756a7f294eb3cade8b0b17
facet_cleaner <- function(p, panel_size = 5, panel_height = 1) {
  p %>% 
    egg::set_panel_size(
      width = grid::unit(panel_size,'cm'), 
      height = grid::unit(panel_height,'null')) %>% 
    gridExtra::arrangeGrob(grid::rectGrob(gp=grid::gpar(col=NA)), ., nrow=1, 
                widths = grid::unit.c(grid::unit(1,'null'), sum(.$widths)))
}

## Create dataset with two groups
d <- tibble::tibble(vals = runif(200, 0, 10), 
          group1 = rep(c("Germany", "United Kingdom",
                      "France", "Belgium", 
                      "Netherlands", "USA",
                      "Russia", "Spain"), 25)) %>% 
  dplyr::mutate(group2 = dplyr::case_when(
    group1 %in% c("Germany", "France", "USA") ~ "Group A", 
    group1 %in% c("Spain", "United Kingdom")~ "Group B",
    T ~ "Group C")) %>% 
  dplyr::group_by(group1) %>% 
  dplyr::mutate(order = 1:dplyr::n()) %>% 
  dplyr::ungroup() 

## ggplot
d %>% 
  ## split by row group
  dplyr::group_split(group2) %>% 
  ## plot each row individually
  purrr::map(~{
    .x %>% 
      ggplot2::ggplot(ggplot2::aes(order, vals)) +
      ggplot2::geom_line() +
      ggplot2::facet_grid(group2~group1)
  }) %>% 
  ## fix facet width and add buffer
  purrr::map(facet_cleaner) %>% 
  ## plot grobs on top of each other
  patchwork::wrap_plots(ncol = 1)
  

Result: