Plotting multiple graphs in R

Question

So I want to plot multiple plots at the same time for each place with Num of Visits on y-axis and Day on x-axis but I'm not sure if there is a function to do this?

So I was able to make a plot for place A by subsetting place A :

placeA <- subset(df$place=="A")

ggplot(data=placeA, aes(x=Day, y=Num_OfVisits, group=1)) +
  geom_line(color="#00AFBB", size=0.5) +
  theme(axis.text.x=element_text(angle=90,hjust=1, size=5))

But now I want to generate a plot for the other places and I am hoping that I could do it all in one shot because there are around 1000 places on my dataset and subsetting is taking some time. Any help will be appreciated. Thank you!

Answer 1

You can write a function that takes the data frame and Place as inputs then loop through all the values in Place column to create the corresponding plots.

library(tidyverse)

df <- data_frame(
  Place = c(rep(c("A", "B", "C"), each = 3)),
  Num_of_Visits = seq(1:9),
  Day = rep(c("Sunday", "Monday", "Tuesday"), 3)
)

df <- df %>% 
  mutate(Day = factor(Day, levels = c("Sunday", "Monday", "Tuesday")))

my_plot <- function(df, myvar) {      
  ggplot(data = df %>% filter(Place == myvar), 
         aes(x = Day, y = Num_of_Visits, group = 1)) +
    geom_line(color = "#00AFBB", size = 0.5) +
    theme(axis.text.x = element_text(angle = 90, vjust = 0.5))      
}

# test
my_plot(df, 'A')

Loop through Place var, create plots & store them in a list using purrr::map()

plot_list <- unique(df$Place) %>% 
  purrr::set_names() %>% 
  purrr::map( ~ my_plot(df, .x))
str(plot_list, max.level = 1)
#> List of 3
#>  $ A:List of 9
#>   ..- attr(*, "class")= chr [1:2] "gg" "ggplot"
#>  $ B:List of 9
#>   ..- attr(*, "class")= chr [1:2] "gg" "ggplot"
#>  $ C:List of 9
#>   ..- attr(*, "class")= chr [1:2] "gg" "ggplot"

Display all plots with purrr::walk()

purrr::walk(plot_list, print)

Save all plots to PNG files using purrr::iwalk()

purrr::iwalk(plot_list,
             ~ ggsave(plot = .x,
                      filename = paste0("Plot_", .y, ".png"),
                      type = 'cairo', width = 6, height = 6, dpi = 150)
)

Combine all plot together if needed using cowplot::plot_grid()

library(cowplot)
do.call(plot_grid, c(plot_list, 
                     align = "h",
                     axis = 'tb',
                     ncol = 3))

^{Created on 2018-10-19 by the reprex package (v0.2.1.9000)}