Create scatterplot matrix using the tidyverse

pairs_plot.R

library(tidyverse)
library(patchwork)

plot_pair <- function(data, x, y) {
  ggplot(data, aes_string(x = x, y = y, color = "Species", shape = "Species")) + 
    geom_point() +
    scale_color_brewer(palette = "Dark2") +
    theme(legend.position = "none", plot.title = element_text(size = 7)) +
    labs(x = NULL, y = NULL, title = paste0(y, " ~ ", x))
}

df <- names(iris) %>% 
  head(-1) %>% 
  list(x = ., y = .) %>% 
  cross_df() %>% 
  mutate(data = list(iris)) %>% 
  mutate(p = pmap(list(data, x, y), plot_pair))

# Add legend to last plot
df$p[[nrow(df)]] <- df$p[[nrow(df)]] + theme(legend.position = "right")

reduce(df$p, `+`)