Pie chart drawing in R

Question

I want to draw a pie chart like below: Pie

A sample of the dataset is like this

structure(list(`Valuation Area` = c("20G5", "20G5", "20G5", "20G5", 
"20G5", "20G5", "20G5", "20G5", "20G5", "20G5", "20G5", "20G5", 
"20G5", "20G5", "20G5"), Backorder = c(15, 6, NA, 7, 5, 14, NA, 
NA, 4, NA, 3, NA, 12, NA, 1), `New higher` = c("yes", "yes", 
"yes", "yes", "yes", "yes", "yes", "no", "yes", "yes", "yes", 
"no", "no", "no", "yes")), row.names = c(NA, -15L), class = c("tbl_df", 
"tbl", "data.frame"))

My step 1,

library(dplyr)
library(tidyr)
library(ggplot2)

dput(Top_purchasing_2021[1:15,c(1,20,24)]) %>%
    drop_na(Backorder) %>%
    summarise(sum_backorder = sum(`Valuation Area` == "20G5"),
              sum_reduce_safetystock = sum(`New higher` == "yes"),
              sum_increase_safetystock = sum_backorder-sum_reduce_safetystock)

My step 2,

df <-  data.frame(group = c("sum_reduce_safetystock", "sum_increase_safetystock"), value = c(8, 1))
bp <-  ggplot(df, aes(x="", y=value, fill=group)) +
  geom_bar(width=2, stat="identity")
bp
pie <- bp + coord_polar("y", start=0) + labs(title="backorder with safety stock")
pie

As can be seen "value=c(8,1)" is what i got from the step 1. when I change the code to below, it still draws the pie but shows error "Error in data.frame(group = c("sum_reduce_safetystock", "sum_increase_safetystock"), : object 'sum_reduce_safetystock' not found"

df <-  data.frame(group = c("sum_reduce_safetystock", "sum_increase_safetystock"), value = c(sum_reduce_safetystock, sum_increase_safetystock))
bp <-  ggplot(df, aes(x="", y=value, fill=group)) +
  geom_bar(width=2, stat="identity")
bp
pie <- bp + coord_polar("y", start=0) + labs(title="backorder with safety stock")
pie

How can I fix this, or can i do it in a better way pls? thank you.

Welcome to SO. It's not easy to help you because 1) we don't have `Top_purchasing_2021` - we can't import your screenshot into R, and we don't know how you imported the file into R either. 2) We also don't have the code you attempted to use to make the pie chart. Can you edit your post to share 1) the output of `dput(head(op_purchasing_2021))`, so we can recreate a sample of your dataset, and 2) the `ggplot2` code you used? Please see [here](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example) for more info — Andrea M, Apr 20 '22 at 07:08
Hi Andrea, sry I am still learning how to ask question in a right way..thanks for the guide. I have edited my question. Does it make more sense now pls? thanks — Bob, Apr 20 '22 at 11:11

score 0 · Accepted Answer · answered Apr 20 '22 at 11:48

ggplot2 can do all the calculations for you, as long as you have the data in long format - you don't need to summarise yourself.

I would simply create the two binary variables that you want to plot, and then let geom_bar do the calculations. ggarrange from ggpubr can then arrange the two charts together.

library(dplyr)
library(ggplot2)

# Create binary variables
Top_purchasing_2021 <- Top_purchasing_2021 |> 
  mutate(backorder = ifelse(is.na(Backorder),
                            "Without backorder",
                            "With backorder"),
         aim = ifelse(`New higher` == "yes",
                      "To reduce safety stock",
                      "To increase safety stock"))

# First pie chart
a <- Top_purchasing_2021 |> 
    ggplot(aes(x = "", y = backorder, fill = backorder)) +
    geom_bar(stat = "identity", width = 1) +
    coord_polar("y", start = 0) +
    theme_void() +
    theme(legend.position = "bottom")

# Second pie chart
b <- Top_purchasing_2021 |>
    filter(backorder == "With backorder") |>
    ggplot(aes(x = "", y = aim, fill = aim)) +
    geom_bar(stat = "identity", width = 1) +
    coord_polar("y", start = 0) +
    theme_void() +
    scale_fill_manual(values = c("coral4", "coral2")) +
    theme(legend.position = "bottom")

# Combine into one
ggpubr::ggarrange(a, b)

NB - pie charts are often not the best data visualisation tool (which is probably why they're not very straightforward to implement in ggplot). See here for more info.

Pie chart drawing in R

1 Answers1