R Markdown document creation in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start an R Markdown document with the correct YAML header.

R Programming

---
title: "My Document"
output: [1]
---

Drag options to blanks, or click blank then click option'

Ahtml_document

Bpdf_document

Cword_document

Dmarkdown_document

Attempts:

3 left

💡 Hint

Common Mistakes

Using an output format not supported by R Markdown

Forgetting to put quotes around the title

The output field specifies the format of the R Markdown output. html_document creates an HTML file.

2fill in blank

medium

Complete the code to insert an R code chunk in R Markdown.

R Programming

```[1]
summary(cars)
```

Drag options to blanks, or click blank then click option'

Asql

Bpython

Cbash

Dr

Attempts:

3 left

💡 Hint

Common Mistakes

Using other languages like python or bash inside R Markdown R chunks

Forgetting the triple backticks

R code chunks start with ```r in R Markdown.

3fill in blank

hard

Fix the error in the YAML header to correctly specify the author.

R Programming

---
title: "Analysis"
author: [1]
output: html_document
---

Drag options to blanks, or click blank then click option'

Aauthor: John Doe

BJohn Doe

C"John Doe"

D'John Doe'

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the author name

Including the key name again inside the value

The author name must be a string in quotes in YAML to be valid.

4fill in blank

hard

Fill both blanks to create a code chunk with echo turned off.

R Programming

```[1] [2]
plot(pressure)
```

Drag options to blanks, or click blank then click option'

Ar

Bpython

Cecho=FALSE

Decho=TRUE

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong language name

Setting echo to TRUE instead of FALSE

The chunk language is r and echo=FALSE hides the code in the output.

5fill in blank

hard

Fill all three blanks to create a YAML header with title, author, and date.

R Programming

---
title: [1]
author: [2]
date: [3]
output: html_document
---

Drag options to blanks, or click blank then click option'

A"My Report"

B"Alice Smith"

C"2024-06-01"

D2024-06-01

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the date

Using unquoted strings in YAML

YAML strings should be quoted. The date is also quoted as a string.

Practice

1. What is the main purpose of an R Markdown document?

easy

A. To store data in a spreadsheet format

B. To write only R code without any text

C. To create interactive web applications

D. To combine text and R code in one file for easy report generation

Solution

1. Step 1: Understand R Markdown's function

   R Markdown allows mixing text and R code in one document.

2. Step 2: Identify the purpose

   This combination is mainly used to create reports easily.

3. Final Answer:

   To combine text and R code in one file for easy report generation -> Option D

4. Quick Check:

   R Markdown = Text + R code for reports [OK]

Hint: Remember: R Markdown = text + code for reports [OK]

Common Mistakes:

• Thinking R Markdown is only for code
• Confusing with Shiny apps
• Assuming it's for data storage

2. Which of the following is the correct way to start an R code chunk in an R Markdown document?

easy

A. <r>```

B. ```r{

C. ```{r}

D. {r}```

Solution

1. Step 1: Recall R code chunk syntax

   R code chunks start with three backticks followed by {r} exactly.

2. Step 2: Match the correct syntax

   ```{r} matches the correct syntax: ```{r}

3. Final Answer:

   ```{r} -> Option C

4. Quick Check:

   Code chunk start = ```{r} [OK]

Hint: Code chunks start with three backticks and {r} [OK]

Common Mistakes:

• Placing {r} after backticks incorrectly
• Using angle brackets instead of backticks
• Missing curly braces

3. Given this R Markdown snippet, what will be the output in the final document?

```{r}
x <- 5
x * 2
```

medium

A. 10

B. x * 2

C. 5

D. Error: object 'x' not found

Solution

1. Step 1: Understand the code chunk execution

   The code assigns 5 to x, then calculates x * 2, which is 10.

2. Step 2: Determine output shown in document

   R Markdown shows the result of the last expression, which is 10.

3. Final Answer:

   10 -> Option A

4. Quick Check:

   5 * 2 = 10 [OK]

Hint: Last expression in chunk shows output [OK]

Common Mistakes:

• Expecting code to print the expression itself
• Confusing variable assignment with output
• Thinking error occurs due to chunk

4. You wrote this R Markdown chunk but get an error when knitting:

```{r}
print('Hello World'
```

What is the problem?

medium

A. Wrong chunk start syntax

B. Missing closing parenthesis in print function

C. Missing quotes around Hello World

D. Code chunk not closed with backticks

Solution

1. Step 1: Check the print statement syntax

   The print function is missing a closing parenthesis.

2. Step 2: Verify chunk syntax

   The chunk start and end are correct; quotes are present.

3. Final Answer:

   Missing closing parenthesis in print function -> Option B

4. Quick Check:

   print('text') needs closing ) [OK]

Hint: Count parentheses carefully in code chunks [OK]

Common Mistakes:

• Ignoring missing parenthesis errors
• Thinking chunk delimiters cause error
• Assuming quotes are missing

5. You want to create an R Markdown document with title "My Report", author "Alex", and output as HTML. Which YAML header is correct?

hard

A. ---
title: "My Report"
author: "Alex"
output: html_document
---

B. ---
title: My Report
author: Alex
output: pdf_document
---

C. ---
title: "My Report"
author: "Alex"
output: word_document
---

D. ---
title: My Report
author: Alex
output: html
---

Solution

1. Step 1: Identify correct YAML format for title, author, output

   YAML requires --- lines, key: value pairs, and output format as html_document for HTML output.

2. Step 2: Match options with correct YAML

   --- title: "My Report" author: "Alex" output: html_document --- uses quotes for strings and output: html_document, which is correct.

3. Final Answer:

   --- title: "My Report" author: "Alex" output: html_document --- -> Option A

4. Quick Check:

   YAML header with html_document output [OK]

Hint: Use output: html_document for HTML in YAML [OK]

Common Mistakes:

• Using pdf_document or word_document instead of html_document
• Missing quotes causing parsing errors
• Incorrect output format name