loop.R

library(tidyverse)
library(gridExtra)

plot_cars_var <- function(col_name){
  ggplot(mtcars, aes_string(x = "mpg", y = col_name)) +
    geom_smooth() +
    geom_point()
}

mtcars %>% 
  dplyr::select(-mpg, everything()) %>% 
  colnames() %>% 
  purrr::map(plot_cars_var) %>% 
  grid.arrange(grobs = ., ncol = 1)

Thanks for the extra example. I ran 2 ways and the gather function ended up being quicker:

> tic()
> df1 %>% 
+     dplyr::select(-Week, everything()) %>% 
+     colnames() %>% 
+     purrr::map(plot_cars_var) %>% 
+     grid.arrange(grobs = ., ncol = 5)

> toc()
11.551 sec elapsed
> tic()
> ggplot(gather(df1, key, value, -Week), aes(Week, value)) + 
+     geom_smooth() + geom_point() +
+     facet_wrap(~ key, scales="free_y", ncol=5)
> toc()
4.039 sec elapsed