Swirl 1.3

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From the course by Johns Hopkins University

Developing Data Products

1405 ratings

Johns Hopkins University

Developing Data Products

1405 ratings

Course 9 of 10 in the Specialization Data Science

A data product is the production output from a statistical analysis. Data products automate complex analysis tasks or use technology to expand the utility of a data informed model, algorithm or inference. This course covers the basics of creating data products using Shiny, R packages, and interactive graphics. The course will focus on the statistical fundamentals of creating a data product that can be used to tell a story about data to a mass audience.

From the lesson

Swirl and Course Project

Week 4 is all about the Course Project, producing a Shiny Application and reproducible pitch.

Meet the Instructors

Brian Caffo, PhD
Professor, Biostatistics
Bloomberg School of Public Health
Jeff Leek, PhD
Associate Professor, Biostatistics
Bloomberg School of Public Health
Roger D. Peng, PhD
Associate Professor, Biostatistics
Bloomberg School of Public Health

So we've created our first lesson and we have tested it, let's get

into some of the more complicated question types that you can ask in a swirl lesson.

And I want to start a new lesson, so in order to do that,

I can close this lesson.yaml file, and

I want to create a lesson in the course that I'm working on.

So just to remind myself of what course I'm working on, I'm going to use

the get_current_lesson function, and that just returns some data about what

lessons and what course swirl knows it's working on right now.

So my course is called My First Course, so let's start a new lesson.

We're going to call this lesson Lesson 2, and

this is still in the My First Course, course.

All right, so, we've got a new lesson here.

I forgot to mention this before,

but this first question that gets generated is called the meta question.

The student never sees it, but

you can just provide some information inside of the meta question.

So I'm going to fill out these fields of the author and the organization.

All right, so now, let's take a look at some more complicated question types.

For example, if I wanted to write a multiple choice question,

I could use wq_multiple, and then coming over here to edit it,

I could ask any kind of multiple choice question here.

So, a simple question like,

Which of these shapes has four sides?

And then, I can separate the different answer choices with semi-colons.

So I'm going to say, Square;Circle.

The answer is Square, and

the answer test here is just repeating what the correct answer is.

And then for the hint, I can just write anything.

I'm going to give a very unhelpful hint.

All right, so I'm going to add this lesson to the course manifest.

Then let's quickly run test_ lesson.

We've got no errors.

And now let's run demo_lesson.

Which of these shapes has four sides?

I have to pick 1, 2, or 3.

If I pick 2, I get the wrong answer.

So I'm going to answer square, and that's the end of the lesson.

Now I'd like to write a figure type question.

So I'm going to type into the R console wq_figure.

And that will add a figure question template to my lesson.yaml.

So the message that I'm going to output to the user is just

going to say, This is a simple graph.

And then there are two more fields that are part of this question,

the Figure and the FigureType.

So the Figure is an R script that I will include in the lesson directory.

And whatever code is in that R script will be executed in order

to show a figure to the student.

And then this FigureType just specifies new to

show that this is going to be a new figure.

In other words, we're not going to be building at all on this figure.

So first, let me add this figure file.

I'm going to call this file fig1, and now let's go over to the Finder.

Actually, let me open up a new R script, in fact,

I have an entitled script right here.

And I'm just going to make a very quick plot, and

then I'm going to save this in My First Course > Lesson_2,

and we're calling it fig1.R, perfect, okay.

So let's demo this lesson again.

So I have to pick square, and then, as you can see, It draws a very simple plot.

Now let's say that I wanted to add something to this plot after I drew it.

I can add another figure question, so I'm going to say,

wq_figure to add another figure question

template, and then I'm going to add a line.

So, what I'm going to show the user is just the text, I added a line!

I'm going to write the code for adding this line in a file called fig2.R.

And this FigureType is add, instead of new.

Those are the only true choices that there are for FigureType.

So let me then open up a new script,

and I'm just going to say abline,

(h = 5, col = "red").

We'll save that as fig2.R.

All right, so let me demo the lesson one more time.

Circle, square,

here's a drawing of the graph.

And then, it draws the line.

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