pie_charts.qmd

# Pie charts {#sec-pie-charts}

```{r}
#| label: setup
#| message: false
#| warning: false
#| include: false
library(tidyverse)
library(lubridate)
library(scales)
library(knitr)
library(kableExtra)
library(colorblindr)
library(downlit)
library(patchwork)
# fonts ----
library(extrafont)
library(sysfonts)
library(fivethirtyeight) 
library(ggmosaic)
source("_common.R")
# use font
showtext::showtext_auto()
# set theme
ggplot2::theme_set(theme_ggp2g(
    base_size = 14))
```

```{r}
#| label: status
#| results: "asis"
#| echo: false
# status ----
# polish, dev, draft, complete
status("complete")
```

:::: {.callout-note collapse="false" icon=false}

<br>

```{r}
#| label: full_code_display
#| eval: true
#| echo: false
#| warning: false
#| message: false
#| out-height: '60%'
#| out-width: '60%'
#| fig-align: right
library(ggplot2movies)
library(ggplot2)
library(ggpubr)
penguins_bar <- palmerpenguins::penguins |> 
    filter(!is.na(species))
movie_pie <- ggplot2movies::movies |>
  filter(mpaa != "" & mpaa != "NC-17") |> 
  group_by(mpaa) |> 
  summarise(cnt = n()) |> 
  mutate(
    perc = round(cnt / sum(cnt), 3),
    mpaa = factor(mpaa, 
          levels = c("PG", "PG-13", "R")))
labs <- paste0(movie_pie$mpaa, " (", 
               (100*movie_pie$perc), "%)")
labs_pie <- labs(
  title = "Percent MPAA ratings for IMDB movies",
  x = "Percent MPAA rating")
ggp2_pie <- ggpubr::ggpie(movie_pie, 
          x = "perc", label = labs, 
          lab.pos = "in", lab.font = "white",
          fill = "mpaa", color = "white") + 
    theme(legend.position = "none")  
    
ggp2_pie + 
  labs_pie
```

::: {style="font-size: 1.10em; color: #02577A;"}
**This graph requires:**
:::

::: {style="font-size: 1.05em; color: #282b2d;"}
**`r emo::ji("check")` a categorical variable**      
:::

::::

## Description 

*“In general, pie charts work well when the goal is to emphasize simple fractions, such as one-half, one-third, or one-quarter.”*

*“They also work well when we have very small datasets.”* - [Claus O. Wilke, Fundamentals of Data Visualization (2019)](https://clauswilke.com/dataviz/)

Pie-charts are ideal for comparing the proportions of categorical variable values, and we can build pie-charts using the [`ggpubr` package.](https://rpkgs.datanovia.com/ggpubr/)

## Set up

::: {style="font-size: 1.15em; color: #1e83c8;"}
**PACKAGES:**
:::

Install packages.


::: {style="font-size: 0.85em;"}
```{r}
#| label: pkg_code_pie
#| code-fold: show
#| eval: false
#| echo: true
#| warning: false
#| message: false
#| results: hide
install.packages("ggpubr")
library(ggpubr)
install.packages("ggplot2movies")
library(ggplot2movies) 
library(ggplot2)
```
:::

::: {style="font-size: 1.15em; color: #1e83c8;"}
**DATA:**
:::

::: {.column-margin}
![](www/imdb.png){fig-align="right" width="35%" height="35%"}
:::

Remove the missing values and `"NC-17"` from `mpaa` and summarise the count and percent.

::: {style="font-size: 0.85em;"}
```{r}
#| label: data_code_pie
#| code-fold: show
#| eval: true
#| echo: true
movie_pie <- ggplot2movies::movies |>
  filter(mpaa != "" & mpaa != "NC-17") |> 
  group_by(mpaa) |> 
  summarise(cnt = n()) |> 
  mutate(
    perc = round(cnt / sum(cnt), 3),
    mpaa = factor(mpaa, 
          levels = c("PG", "PG-13", "R")))
glimpse(movie_pie)
```
:::

## Grammar

::: {style="font-size: 1.15em; color: #1e83c8;"}
**CODE:**
:::

  -   Create labels with `labs()`

  -   Initialize the graph with `ggplot()` and provide `data`

  -   Assign `"perc"` to `x`

  -   Assign `labs` to `label`

  -   Assign `"in"` to `lab.pos`

  -   Assign `"white"` to `lab.font` and `color`

  -   Assign `"mpaa"` to `fill`

  -   Remove legend with `theme(legend.position = "none")`

::: {style="font-size: 0.85em;"}
```{r}
#| label: code_graph_pie
#| code-fold: show
#| eval: false
#| echo: true 
#| warning: false
#| message: false
#| out-height: '100%'
#| out-width: '100%'
labs <- paste0(movie_pie$mpaa, " (", 
               (100*movie_pie$perc), "%)")
labs_pie <- labs(
  title = "Percent MPAA ratings for IMDB movies",
  x = "Percent MPAA rating")

ggp2_pie <- ggpubr::ggpie(movie_pie, 
          x = "perc", label = labs, 
          lab.pos = "in", lab.font = "#ffffff",
          fill = "mpaa", color = "#ffffff") + 
    theme(legend.position = "none")  
    
ggp2_pie + 
  labs_pie
```
:::



::: {style="font-size: 1.15em; color: #1e83c8;"}
**GRAPH:**
:::

```{r}
#| label: create_graph_pie
#| eval: true
#| echo: false
#| warning: false
#| message: false
#| out-height: '100%'
#| out-width: '100%'
#| layout-nrow: 1
#| column: page-inset-right
labs <- paste0(movie_pie$mpaa, " (", 
               (100*movie_pie$perc), "%)")
labs_pie <- labs(
  title = "Percent MPAA ratings for IMDB movies",
  x = "Percent MPAA rating")

ggp2_pie <- ggpubr::ggpie(movie_pie, 
          x = "perc", label = labs, 
          lab.pos = "in", lab.font = "#ffffff",
          fill = "mpaa", color = "#ffffff") + 
    theme(legend.position = "none")  
    
ggp2_pie + 
  labs_pie
```