Using R with Quarto – Rahul Saraf

Quarto

Quarto enables you to weave together content and executable code into a finished document. To learn more about Quarto see https://quarto.org.

Running Code

When you click the Render button a document will be generated that includes both content and the output of embedded code. You can embed code like this:

library(tidyverse)

── Attaching core tidyverse packages ──────────────────────── tidyverse 2.0.0 ──
✔ dplyr     1.1.2     ✔ readr     2.1.4
✔ forcats   1.0.0     ✔ stringr   1.5.0
✔ ggplot2   3.4.2     ✔ tibble    3.2.1
✔ lubridate 1.9.2     ✔ tidyr     1.3.0
✔ purrr     1.0.1     
── Conflicts ────────────────────────────────────────── tidyverse_conflicts() ──
✖ dplyr::filter() masks stats::filter()
✖ dplyr::lag()    masks stats::lag()
ℹ Use the conflicted package (<http://conflicted.r-lib.org/>) to force all conflicts to become errors

You can add options to executable code like this

mpg

# A tibble: 234 × 11
   manufacturer model      displ  year   cyl trans drv     cty   hwy fl    class
   <chr>        <chr>      <dbl> <int> <int> <chr> <chr> <int> <int> <chr> <chr>
 1 audi         a4           1.8  1999     4 auto… f        18    29 p     comp…
 2 audi         a4           1.8  1999     4 manu… f        21    29 p     comp…
 3 audi         a4           2    2008     4 manu… f        20    31 p     comp…
 4 audi         a4           2    2008     4 auto… f        21    30 p     comp…
 5 audi         a4           2.8  1999     6 auto… f        16    26 p     comp…
 6 audi         a4           2.8  1999     6 manu… f        18    26 p     comp…
 7 audi         a4           3.1  2008     6 auto… f        18    27 p     comp…
 8 audi         a4 quattro   1.8  1999     4 manu… 4        18    26 p     comp…
 9 audi         a4 quattro   1.8  1999     4 auto… 4        16    25 p     comp…
10 audi         a4 quattro   2    2008     4 manu… 4        20    28 p     comp…
# ℹ 224 more rows

The echo: false option disables the printing of code (only output is displayed).

This is a hello world document for using R in quarto. I love it very much.

Creating a ggplot

Creating the first ggplot with mpg data.

ggplot(data = mpg)+
  geom_point(mapping = aes(x = displ, y = hwy))

Run ggplot(data = mpg). What do you see?

We see an empty plot as below
```
ggplot(data=mpg)
```

How many rows are in mpg? How many columns?

nrow(mpg)

[1] 234

ncol(mpg)

[1] 11

dim(mpg)

[1] 234  11

What does the drv variable describe? Read the help for ?mpg to find out. drv -> the type of drive train, where f = front-wheel drive, r = rear wheel drive, 4 = 4wd
Make a scatterplot of hwy vs cyl.

hwy

highway miles per gallon

cyl

number of cylinders
```
ggplot(data=mpg)+geom_point(mapping = aes(x = hwy, y = cyl))
```
What happens if you make a scatterplot of class vs drv? Why is the plot not useful

drv

the type of drive train, where f = front-wheel drive, r = rear wheel drive, 4 = 4wd

class

“type” of car
```
ggplot(data=mpg)+geom_point(mapping = aes(x = class, y = drv))
```
There is no trend or any decipherable relationship between drv and class among different class categories.

Aesthetics

ggplot(data = mpg)+
  geom_point(mapping = aes(x = displ, y = hwy, color = class))

# Left
ggplot(data = mpg) + 
  geom_point(mapping = aes(x = hwy, y = displ, color = class))
# Right
ggplot(data = mpg) + 
  geom_point(mapping = aes(x = displ, y = hwy, color = class))