Code chunks and output in R Programming - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a code chunk in R Markdown?

A code chunk is a section in R Markdown where you write R code that will be run when the document is knitted. It starts with ```{r} and ends with ```.

beginner

How do you show the output of a code chunk in the knitted document?

By default, the output of the code inside a chunk is shown below the code when you knit the document.

beginner

What does the chunk option `echo=FALSE` do?

It hides the R code in the output but still shows the results of running the code.

intermediate

How can you prevent both code and output from showing in the final document?

Use chunk options `echo=FALSE` and `results='hide'` together to hide both code and output.

intermediate

What is the purpose of the chunk option `eval=FALSE`?

It prevents the code inside the chunk from running, so no output or results are generated.

In R Markdown, which symbol starts a code chunk?

A ```{r}

B ~~~{r}

C <code>

D //{r}

Code chunks in R Markdown start with three backticks followed by {r}.

What happens if you set `echo=FALSE` in a code chunk?

A Code runs twice

B Code and output are both hidden

C Code is shown but output is hidden

D Code is hidden but output is shown

Setting echo=FALSE hides the code but still shows the output.

Which chunk option stops the code from running?

A eval=FALSE

B echo=FALSE

C results='hide'

D include=FALSE

eval=FALSE prevents the code from running, so no output is produced.

How do you hide both code and output in a chunk?

A echo=TRUE only

B echo=FALSE and results='hide'

C eval=FALSE only

D No option needed

Using echo=FALSE hides code and results='hide' hides output.

What is the default behavior of code chunks in R Markdown?

A Show output only

B Hide code and output

C Show code and output

D Show code only

By default, both code and output are shown in the knitted document.

Explain what a code chunk is and how its output appears in an R Markdown document.

Think about how you write and run R code inside a document.

Describe how to control the visibility of code and output using chunk options.

Chunk options let you decide what the reader sees.