Practice

11.4 Quiz: R

  1. What package contains the functions select, filter & mutate?

    • dplyr (or tidyverse)

  2. Assume I have created some R project and I read a file with the following command - what does this tell you about the folder on my computer?

    greatdata <- readr::read_csv(file = "./data/somefile.CSV")
    • The folder containing the R project contains a subfolder called "data" and in there is a CSV file called "somefile.csv".

  3. I want to load a csv file into R with readRDS(). Why isn't it working?

    • The read commands are specific to the file format. readRDS() is for R files, read.csv() or readr::read_csv() are needed for csv files

  4. What do you know when you look at the command bigfive$extraversion?

    • There is a data set called bigfive and we're accessing a variable called extraversion

  5. What keywords for loops and conditionals do you remember?

    • for, while, if, else, ifelse...

  6. I want to calculate a t-test on soul-belief (yes or no) and age in our seminar data. Why won't this command work?

    t.test(v02_age, soul_dummy, data = seminar)
    • When we have a grouping variable like soul_dummy, we need to use formula notation: v02_age ~ soul_dummy

11.5 Quiz: R Markdown

  1. What do I need to do to make my text look like this?
    • **_look like this_**
  2. I want to add a subtitle to my document, where might I do that?
    • Add 'subtitle: "A great subtitle" ' to the YAML header
  3. How do I generate a section header in my document?
    • With the pound sign # Header
  4. Oh no, my header isn't showing up right! What could have happened?
    • There needs to be a space between the # and the header

11.6 Loops: Write a for-loop that outputs the first X numbers of the Fibonacci sequence ("golden ratio")

Fibonacci Spiral
Fibonacci Spiral

The Fibonacci sequence is defined as a sequence in which each number is the sum of the two proceeding ones. That means, starting at 1 the sequence is: 1, 1, 2, 3, 5, 8, 13... Please create it for the first 15 numbers in the Fibonacci sequence and save the numbers to a variable called fibonacci.

More info: https://en.wikipedia.org/wiki/Fibonacci_sequence.

n <- 15

# Simple and clear
fibonacci <- c(1, 1, rep(NA, n-2))

for(i in 3:n){
  fibonacci[i] <- fibonacci[i-1] + fibonacci[i-2]
}
fibonacci
#  [1]   1   1   2   3   5   8  13  21  34  55  89 144 233 377 610

# Alternative with while loop
fibonacci = c(1, 1)

while(length(fibonacci) < n){
  new_num <- fibonacci[length(fibonacci)] + fibonacci[length(fibonacci) - 1]
  fibonacci <- c(fibonacci, new_num)
}
fibonacci
#  [1]   1   1   2   3   5   8  13  21  34  55  89 144 233 377 610

11.7 RMarkdown: Start your document in a certain way that matches the template!


Look at the example document shown below and try to re-create it! Be mindful of which elements need to be defined in the YAML header and which need to be modified in the text.

Rmd Example Template
Rmd Example Template
---
title: "Exercise 1"
author: "A great author"
date: "2024-07-02"
output: 
  pdf_document:
    toc: true
---

# First Chapter

Some text in **bold**.

## A subchapter

Some text in _cursive_.

# Second Chapter

Here is an overview of the iris dataset:

``{r} # make sure to include three ` here!
head(iris, 3)
``
Hadley Wickham GIFfrom Hadley GIFs