What is inside RMarkdown in more detail?

01

# What is inside RMarkdown in more detail?

---

# How does R Markdown work - what do you think?

1. 🤷

1. I press knit, a document appears, and I believe that anything happening in between could be actual magic.

1. `knitr` executes the code and converts `.Rmd` to `.md`; **Pandoc** renders the `.md` file to the output format you want.

]

---

]

# How *does* R Markdown work - answers?

1. 🤷 (✔️)

1. ["I press knit, a document appears, and I believe that anything happening in between could be actual magic."](https://twitter.com/allison_horst/status/1070323369600442368?s=20) (🧙‍♂️)

1. `knitr` executes the code and converts `.Rmd` to `.md`; **Pandoc** renders the `.md` file to the output format you want. (✔️)

]

---

# <center>Metadata</center>

1

---

# Metadata - YAML

_"YAML Ain't Markup Language"_

```yaml
---
key: value
---
```

]

]

???

Using the {ymlthis} this section renders the "look" of the YAML with the three 
dashes then `key: value` which is the format used in YAML.

---
class: middle, center

# Output options

---

# Save output options in your YAML

Basic YAML

```yaml
---
title: The Great British Bake Off
output: html_document
---
```

]

--
.pull-right[

Add html related options

```yaml
---
title: The Great British Bake Off
output:
  html_document:
    toc: true
---
```

]

---
class: your-turn

# Your turn

## Add output options to YAML

Use `?rmarkdown::html_document` from your R console to find the code to:

1. Add a floating table of contents

1. Add a theme

🧶 **Knit** to HTML to see the output.

**If this was easy**, try to embed the `Rmd` source code to download (appears as
a button in top right hand of report).

_psst...answers on the next slide..._

---
class: your-turn

# Answers

```yaml
---
title: The Great British Bake Off
output:
  html_document:
    toc: true
    toc_float: true
    theme: flatly
    code_download: true
---
```

???

Copying the code to MS Teams to share will lose the formatting!

---

# <center>Parameters</center>

2

---

# <center>Parameters</center>

```yaml
---
title: The Great British Bake Off
output:
  html_document:
    toc: true
    toc_float: true
    theme: flatly
    code_download: true
params:
  series: '1'
---
```

???

Some may be familiar to the concept of parameters from SQL where code use in multiple
places later in the script are written at the top so they can be easily changed.

This is a particular example of this 'hard coding' of parameters.

---
class: your-turn

# Your turn

Change this:

```yaml
---
title: The Great British Bake Off
output:
  html_document:
    toc: true
    toc_float: true
    theme: flatly
    code_download: true
params:
  series: '1'
---
```

]

To this:

```yaml
---
title: The Great British Bake Off
output:
  html_document:
    toc: true
    toc_float: true
    theme: flatly
    code_download: true
params:
  series: '2'
---
```

]

Now click on knit button and pick __"Knit with Parameters."__ How is this different from what you did above?

Note: this might appear as a grey box if your VPN/Network has strict security

---

# ⏱

# Time for a break!

---
class: inverse

# <center>Next section...</center>