Chapter 1 Prerequisites

This is a sample book written in Markdown. You can use anything that Pandoc’s Markdown supports, e.g., a math equation \(a^2 + b^2 = c^2\).

The bookdown package can be installed from CRAN or Github:

install.packages("bookdown")
# or the development version
# devtools::install_github("rstudio/bookdown")

Remember each Rmd file contains one and only one chapter, and a chapter is defined by the first-level heading #.

To compile this example to PDF, you need XeLaTeX. You are recommended to install TinyTeX (which includes XeLaTeX): https://yihui.org/tinytex/.

head(iris)
##   Sepal.Length Sepal.Width Petal.Length Petal.Width Species
## 1          5.1         3.5          1.4         0.2  setosa
## 2          4.9         3.0          1.4         0.2  setosa
## 3          4.7         3.2          1.3         0.2  setosa
## 4          4.6         3.1          1.5         0.2  setosa
## 5          5.0         3.6          1.4         0.2  setosa
## 6          5.4         3.9          1.7         0.4  setosa
library(tidyverse)
## -- Attaching packages --------------------------------------- tidyverse 1.3.0 --
## √ ggplot2 3.3.3     √ purrr   0.3.4
## √ tibble  3.1.0     √ dplyr   1.0.4
## √ tidyr   1.1.2     √ stringr 1.4.0
## √ readr   1.4.0     √ forcats 0.5.1
## -- Conflicts ------------------------------------------ tidyverse_conflicts() --
## x dplyr::filter() masks stats::filter()
## x dplyr::lag()    masks stats::lag()
iris %>%
  pivot_longer(cols = -Species, names_to = "Part", values_to = "Value") %>%
  separate(col = "Part", into = c("Part", "Measure"))
## # A tibble: 600 x 4
##    Species Part  Measure Value
##    <fct>   <chr> <chr>   <dbl>
##  1 setosa  Sepal Length    5.1
##  2 setosa  Sepal Width     3.5
##  3 setosa  Petal Length    1.4
##  4 setosa  Petal Width     0.2
##  5 setosa  Sepal Length    4.9
##  6 setosa  Sepal Width     3  
##  7 setosa  Petal Length    1.4
##  8 setosa  Petal Width     0.2
##  9 setosa  Sepal Length    4.7
## 10 setosa  Sepal Width     3.2
## # ... with 590 more rows
iris %>%
  pivot_longer(cols = -Species, names_to = "Part", values_to = "Value") %>%
  separate(col = "Part", into = c("Part", "Measure")) %>%
  group_by(Species, Part) %>%
  summarize(m = mean(Value))
## `summarise()` has grouped output by 'Species'. You can override using the `.groups` argument.
## # A tibble: 6 x 3
## # Groups:   Species [3]
##   Species    Part      m
##   <fct>      <chr> <dbl>
## 1 setosa     Petal 0.854
## 2 setosa     Sepal 4.22 
## 3 versicolor Petal 2.79 
## 4 versicolor Sepal 4.35 
## 5 virginica  Petal 3.79 
## 6 virginica  Sepal 4.78
iris %>%
  pivot_longer(cols = -Species, names_to = "Part", values_to = "Value") %>%
  separate(col = "Part", into = c("Part", "Measure")) %>%
  ggplot(aes(x = Value, color = Part)) + geom_boxplot()