Creating interactive courses for data analysis with R can and should be easy. This tutorial explains how you can create interactive courses on the DataCamp platform. Furthermore, the tutorial explains the Submission Correctness Test - the key concept to add interactivity to your course or tutorial.

Courses are created locally using R Markdown files and managed with a complementary web interface on datacamp.com.

• The R interface - Use R Markdown and the datacamp R package to create interactive courses:
  The datacamp R package enables you to write interactive R courses in R Markdown (e.g. using RStudio locally) and then upload them to the datacamp.com platform. The DataCamp package is essentially a wrapper around the slidify package. This way, you can also use existing R Markdown files as the basis of your interactive courses, and collaborate easily with others on courses (e.g. by sharing the Markdown files on github). Have a look at the R Markdown files of the "Introduction to R" course.
• The web interface - Course management:
  After uploading chapters to datacamp.com, you can use the webinterface to view and organize your courses with their chapters. You can use this interface to make sure your course was uploaded correctly, make various changes to the course's state and get a preview on how the user will see the course.

###Install the datacamp R package

install.packages("devtools")
library("devtools")
install_github("datacampSCT", "data-camp")
install_github("datacamp", "data-camp")
install_github("slidify", "ramnathv", ref = "dev")
install_github("slidifyLibraries", "ramnathv")
library("datacamp")

The code above will download and install the datacamp R package. Alternatively, you can also download the source code above.

###Scaffold a course with chapter

author_course("course_name")

The author_course function will:

1. create a folder in you current working directory with the name "course_name"
2. create a course.yml file, a scaffold to create your course
3. create a chapter1.Rmd file, a scaffold for creating your first chapter The generated template contains extra instructions on the building blocks of chapters. We strongly advise you to put your folder under git source control at this point.

###Directory structure Every course consists of a course.yml file along with various .Rmd chapter files. An example course is structured as follows:

.
|__ course.yml
|__ chapter1.Rmd
|__ chapter2.Rmd
|__ chapter3.Rmd
|__ ...

Note that the chapter .Rmd files can have any chosen name.

###Log in to datacamp.com

datacamp_login()

This will prompt you for your username and password and log you in to the datacamp server. Note that you must also log into datacamp.com with your browser.

###The course.yml file This file contains information about your course and the structure of its chapters. After running author_course(), a course.yml file is created in your course directory. This course.yml file has the following scaffold:

# course.yml scaffold
title: Insert the course title here
author_field: The author(s) name(s)
description: Insert course description here

Change the fields and call the function upload_course(). This will create your course and add its id to the course.yml file. This way your local course is linked to the one on datacamp.com.

# course.yml after creation on server
id: 314
title: Hello world
author_field: Your name
description: A first course

###Uploading chapters to datacamp.com Every chapter is described in its corresponding chapterX.Rmd file. The first time you create a chapter, it's a good idea to start from the chapter1.Rmd template that was generated using author_course("course_name"). This template contains information about the markup language, different types of exercises, etc.

# chapter1.Rmd scaffold
--- 
title_meta  : Insert chapter preposition here
title       : Insert the chapter title here
description : What is this chapter about? Add here your description
framework   : datacamp
mode        : selfcontained

---
## The title of the first exercise
...

Adapt the scaffold and use the function upload_chapter("chapter1.Rmd") to add the chapter to your course on datacamp.com. This will create the chapter and add it to the course.yml file. Every time you add a new chapter to a course, it is added to the course.yml file. An example:

# e.g. course.yml
id: 314
title: Hello world
author_field: Your name
description: A first course
chapters:
- chapter1.Rmd: 753
- chapter2.Rmd: 760

As you can see, the file contains a list of chapters with a mapping of their file names on their id. The order of the list dictates the order of the chapters within the course. This helps you organize your course and avoid overwriting chapters. For example, say we want chapter 2 to appear first on datacamp.com:

# course.yml
...
chapters:
  - chapter2.Rmd: 760
  - chapter1.Rmd: 753

Any changes to this list requires the course to be uploaded with upload_course() for changes to take effect.

###Share the love A course is just a collection of chapters, and a chapter is essentially just a simple R markdown document. Therefore, you can easily collaborate with others on a course. For example, by sharing the R markdown documents on github. We believe this "open-course" type of collaboration for interactive R and statistics courses will benefit everyone. Check out the open-source repo of our Introduction to R course and help us improve it.

The key ingredient to an interactive course is the Submission Correctness Test (SCT). For all information regarding SCTs, please refer to the datacampSCT package.

##Most frequently asked questions

#####How can I create a new chapter? First, make sure the current working directory matches with the course directory you want to create a chapter for. Next, add a new chapter to the course with the help of the author_chapter("chapter_name") function. This will create and open an R Markdown file named chapter_name.Rmd.

# Make sure to set the correct working directory

# Add a new chapter "R for dummies". This will open an R Markdown file.
author_chapter("R_for_dummies")

#####My chapter is finished, how do I upload it to the DataCamp platform? If you already placed your course on the online DataCamp platform, you can upload a new or existing chapter via the function upload_chapter("chapter_name"). If your course is not yet on the online DataCamp platform, you first need to run the command upload_course().

# Upload the chapter "R for dummies"
upload_chapter("R_for_dummies.Rmd")

#####I want to remove a chapter in my course. Can I do this? Yes you can! To remove chapters out of a course, you need to go to your course.yml file. Here you see a list of all the chapters included in your course (in this case two), with their chapter ID:

# e.g. course.yml
id: 314
title: Hello world
author_field: Your name
description: A first course
chapters:
  - chapter1.Rmd: 753
  - chapter2.Rmd: 760

To remove a chapter from a course, you just need to remove the corresponding chapter name and ID in the Yaml file. So suppose you want to remove chapter1.Rmd from the course, your Yaml file needs to look like this:

# e.g. course.yml
id: 314
title: Hello world
author_field: Your name
description: A first course
chapters:
  - chapter2.Rmd: 760

To make these changes visible on the DataCamp platform, you need to re-upload the course via upload_course().

Note: Removing the first chapter from the Yaml file, does not remove the R Markdown file chapter1.Rmd in your course map. So chapter content will not get lost, and you can always re-add the chapter in a later phase.

## First Exercise
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## First Exercise
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# AFTER SCT OF EXERCISE ONE, PLACE THE `---` SIGN TO INDICATE START EXERCISE TWO:
---
## Second Exercise
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*** =sct

## First Exercise
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---
## Second Exercise
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## First Exercise
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*** =sct