CODEWITHSUNDEEP
rggplot2dplyr
moadeep
moadeep

Reputation: 4118

R: Using dplyr group_by with ggplot2 and changing title per group

I have the following example dataframe df_summarised which in reality will have more years and Isotope data.

structure(list(Isotope = c("TC99M", "TC99M", "TC99M", "TC99M", 
"TC99M", "TC99M", "TC99M", "TC99M", "TL201", "TL201", "TL201", 
"TL201", "TL201", "TL201", "TL201", "TL201"), month = structure(c(1L, 
2L, 3L, 4L, 5L, 6L, 7L, 8L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L), .Label = c("Jan", 
"Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", 
"Nov", "Dec"), class = c("ordered", "factor")), year = c(2021, 
2021, 2021, 2021, 2021, 2021, 2021, 2021, 2021, 2021, 2021, 2021, 
2021, 2021, 2021, 2021), TotalMonthlyExcretion = c(17705.648, 
20717.156, 27443.508, 19528.556, 22711.792, 20083.524, 17791.076, 
9223.8, 163.695, 738.51, 1055.775, 906.438, 482.082, 741.984, 
605.211, 265.641), MonthlyLimits_MBq = c(80000, 80000, 80000, 
80000, 80000, 80000, 80000, 80000, 5600, 5600, 5600, 5600, 5600, 
5600, 5600, 5600)), .Names = c("Isotope", "month", "year", "TotalMonthlyExcretion", 
"MonthlyLimits_MBq"), row.names = c(NA, -16L), class = "data.frame")

I want to create an individual plot for each isotope, year combination and save as a separate png file. For each isotope/year pairing, I want to change the title to reflect the pairing. I have tried the following:

ActivityPlots <- df_summarised %>%
    group_by(Isotope,year) %>%
    do(
       plots = ggplot(data=., aes(x=month,y=TotalMonthlyExcretion)) +
       geom_bar(stat="identity", width = .5, fill="tomato3") +
       labs(title = paste("Liquid Radioactive Waste. Year: ", df_summarised$year," Isotope: ", df_summarised$Isotope),
           x = "Month",
           y = "Total Monthly Excretion (MBq)",
           caption = paste("Year: ",df_summarised$year)
           ) +
       theme_bw() +
       theme(
            plot.title = element_text(color="black", size=14, face="bold.italic"),
            axis.title.x = element_text(size=14, face="bold"),
            axis.title.y = element_text(size=14, face="bold"))
       )

However, the plot title for each plot is the same: 'Liquid Radioactive Waste. Year 2021 Isotope TC99M'. I'm assuming this is picking up the values from the first entry of the data frame.

What is the best way around this?

Upvotes: 2

Views: 432

Answers (1)

Ronak Shah
Ronak Shah

Reputation: 389335

Use split and map. To save the plots as png you can include ggsave.

library(tidyverse)

df_summarised %>%
  group_split(Isotope,year) %>%
  map(~{
    plots = ggplot(data=.x, aes(x=month,y=TotalMonthlyExcretion)) +
      geom_bar(stat="identity", width = .5, fill="tomato3") +
      labs(title = paste("Liquid Radioactive Waste. Year: ", .x$year[1]," Isotope: ", .x$Isotope[1]),
           x = "Month",
           y = "Total Monthly Excretion (MBq)",
           caption = paste("Year: ",.x$year[1])
      ) +
      theme_bw() +
      theme(
        plot.title = element_text(color="black", size=14, face="bold.italic"),
        axis.title.x = element_text(size=14, face="bold"),
        axis.title.y = element_text(size=14, face="bold"))
    
    ggsave(sprintf('plots%s_%s.png', .x$Isotope[1], .x$year[1]), plots)
  })

Upvotes: 3

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