Teaching an Introductory Data Science course with tidyverse workshop

# Teaching an Introductory Data Science course with tidyverse workshop
## Data Visualization
### Dr. Mine Dogucu
### 2021-12-15

---

<div class="my-header"></div>

<div class="my-footer"> 
 CC BY-NC-ND 4.0 <a href="https://mdogucu.ics.uci.edu">Mine Dogucu</a></div>

---

[How LGBTQ+ hate crime is committed by young people against young people](https://www.bbc.com/news/uk-46543874)

[Why Time Flies](https://maximiliankiener.com/digitalprojects/time/)

[Mandatory Paid Vacation](https://www.instagram.com/p/CE1kpM5FhWR/?utm_source=ig_web_copy_link)

[Why are K-pop groups so big?](https://pudding.cool/2020/10/kpop/)

---

Data Visualizations

- are graphical representations of data

- use different colors, shapes, and the coordinate system to summarize data

- tell a story

- are useful for exploring data

---

First I go over different types of visualizations so that students can interpret what they see in the visuals.

The following is a useful resource for understanding histograms.

[Exploring Histograms Interactively](http://tinlizzie.org/histograms/)

---

__gg__plot is based on __g__rammar of __g__raphics.

---

## Data

```r
glimpse(titanic)
```

```
## Rows: 891
## Columns: 6
## $ survived <lgl> FALSE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE,…
## $ pclass   <chr> "Third", "First", "Third", "First", "Third", …
## $ sex      <fct> sex, sex, sex, sex, sex, sex, sex, sex, sex, …
## $ age      <dbl> 22, 38, 26, 35, 35, NA, 54, 2, 27, 14, 4, 58,…
## $ fare     <dbl> 7.2500, 71.2833, 7.9250, 53.1000, 8.0500, 8.4…
## $ embarked <fct> Southampton, Cherbourg, Southampton, Southamp…
```

---

class:inverse middle

---

.left-panel[
<br>
<br>
If you could speak to R in English, how would you tell R to make this plot for you?

If you had the data and had to draw this bar plot by hand, what would you do?

]

![](2-data-viz_files/figure-html/unnamed-chunk-4-1.png)
]

---

**3 Steps of Making a Basic ggplot**

1.Pick data

2.Map data onto aesthetics

3.Add the geometric layer

---
class: middle

### Step 1 - Pick Data

```r
ggplot(data = titanic)
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-6-1.png)

]

---

### Step 2 - Map Data to Aesthetics

```r
ggplot(data = titanic,
*      aes(x = pclass))
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-8-1.png)

]

---

### Step 3 - Add the Geometric Layer

```r
ggplot(data = titanic,
       aes(x = pclass)) +
* geom_bar()
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-10-1.png)
]
---

.panel[
.panel-name[Plot]
<img src="2-data-viz_files/figure-html/unnamed-chunk-11-1.png" style="display: block; margin: auto;" />

]

- Create a ggplot using the `titanic` data frame.
- Map the `pclass` to the x-axis. 
- Add a layer of a bar plot.

]

```r
ggplot(data = titanic,
       aes(x = pclass)) +
  geom_bar()
```

]

]
---

class:inverse middle

---

```
## `stat_bin()` using `bins = 30`. Pick better value with
## `binwidth`.
```

]

- Create a ggplot using the `titanic` data frame.
- Map the `fare` to the x-axis. 
- Add a layer of a histogram.

]

```r
ggplot(data = titanic,
       aes(x = fare)) +
  geom_histogram() 
```

]

---
class: middle

### Step 1 - Pick Data

```r
ggplot(data = titanic)
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-16-1.png)

]

---

### Step 2 - Map Data to Aesthetics

```r
ggplot(data = titanic,
*      aes(x = fare))
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-18-1.png)

]

---

### Step 3 - Add the Geometric Layer

```r
ggplot(data = titanic,
       aes(x = fare)) +
* geom_histogram()
```
]

```
## `stat_bin()` using `bins = 30`. Pick better value with
## `binwidth`.
```

![](2-data-viz_files/figure-html/unnamed-chunk-20-1.png)
]

---

## What is this warning?

```
## `stat_bin()` using `bins = 30`. Pick better value with
## `binwidth`.
```

---

```r
ggplot(data = titanic,
       aes(x = fare)) +
* geom_histogram(binwidth = 15)
```

---

]

]

]

]

---

Pick your favorite color(s) from the list at:

[bit.ly/colors-r](https://bit.ly/colors-r)

---

```r
ggplot(data = titanic,
       aes(x = fare)) +
  geom_histogram(binwidth = 15, 
*                color = "white")
```

---

```r
ggplot(data = titanic,
       aes(x = fare)) +
  geom_histogram(binwidth = 15, 
*                fill = "darkred")
```

---

```r
ggplot(data = titanic,
       aes(x = fare)) +
  geom_histogram(binwidth = 15, 
*                color = "white",
*                fill = "darkred")
```

---

---

## Stacked Bar-Plot

```r
ggplot(data = titanic,
       aes(x = pclass, 
*          fill = survived)) +
  geom_bar() 
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-30-1.png)
]

---

## Standardized Bar Plot

```r
ggplot(data = titanic,
       aes(x = pclass, 
           fill = survived)) + 
* geom_bar(position = "fill")
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-32-1.png)
]

---

## Dodged Bar Plot

```r
ggplot(data = titanic,
       aes(x = pclass, 
           fill = survived)) + 
* geom_bar(position = "dodge")
```
]

![](2-data-viz_files/figure-html/unnamed-chunk-34-1.png)
]

---

## New Data

---

## New Data

```r
glimpse(penguins)
```

```
## Rows: 344
## Columns: 8
## $ species           <fct> Adelie, Adelie, Adelie, Adelie, Adel…
## $ island            <fct> Torgersen, Torgersen, Torgersen, Tor…
## $ bill_length_mm    <dbl> 39.1, 39.5, 40.3, NA, 36.7, 39.3, 38…
## $ bill_depth_mm     <dbl> 18.7, 17.4, 18.0, NA, 19.3, 20.6, 17…
## $ flipper_length_mm <int> 181, 186, 195, NA, 193, 190, 181, 19…
## $ body_mass_g       <int> 3750, 3800, 3250, NA, 3450, 3650, 36…
## $ sex               <fct> male, female, female, NA, female, ma…
## $ year              <int> 2007, 2007, 2007, 2007, 2007, 2007, …
```

---

---

---

```
## Warning: Removed 2 rows containing non-finite values
## (stat_ydensity).
```

]

- Create a ggplot using the `penguins` data frame.
- Map the `species` to the x-axis and `bill_length_mm` to the y-axis. 
- Add a layer of a violin plot.

]

```r
ggplot(penguins,
       aes(x = species,
           y = bill_length_mm))  +
  geom_violin()
```

]

---

```
## Warning: Removed 2 rows containing non-finite values
## (stat_boxplot).
```

]

- Create a ggplot using the `penguins` data frame.
- Map the `species` to the x-axis and `bill_length_mm` to the y-axis. 
- Add a layer of a box plot.

]

```r
ggplot(penguins,
       aes(x = species,
           y = bill_length_mm))  +
  geom_boxplot()
```

]

---

]

---
class: inverse middle

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm))  +
  geom_point()
```

]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

![](2-data-viz_files/figure-html/unnamed-chunk-45-1.png)

]

---
class: middle inverse

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           color = species)) +
  geom_point()
```

]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

![](2-data-viz_files/figure-html/unnamed-chunk-47-1.png)

]

---
.left-panel[

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species)) +
  geom_point()
```

]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

![](2-data-viz_files/figure-html/unnamed-chunk-49-1.png)

]

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species)) +
  geom_point()
```

]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

![](2-data-viz_files/figure-html/unnamed-chunk-51-1.png)

]

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species)) +
  geom_point()
```

]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

![](2-data-viz_files/figure-html/unnamed-chunk-53-1.png)

]

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species,
           size = body_mass_g)) +
  geom_point()
```

]

```
## Warning: Removed 2 rows containing missing values (geom_point).
```

![](2-data-viz_files/figure-html/unnamed-chunk-55-1.png)
]
---

---

## Practice

Using either the `babies`, `titanic` or `penguins` data frame ask a question that you are interested in answering. Visualize data to get a visual answer to the question. What is the visual telling you? Note all of this down in your lecture notes.

---

]

.panel-name[English]
- Using the `penguins` data,   
- Map `bill depth` to x-axis, `bill length` to y-axis, `species` to shape and color.
- Add a layer of points and set the size of the points to 4.
]

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species)) +
  geom_point(size = 4) 
```

]

---

## Labs

]

.panel-name[English]
- Using the `penguins` data,   
- Map `bill depth` to x-axis, `bill length` to y-axis, `species` to shape.
- Add a layer of points and set the size of the points to 4.
- .highlight-text[Add labels to x-axis (Bill Depth(mm)), y-axis (Bill Length(mm)), and the title of the plot (Palmer Penguins).]

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species)) +
  geom_point(size = 4) +
* labs(x = "Bill Depth (mm)",
*      y = "Bill Length (mm)",
*      title = "Palmer Penguins")
```

]

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species)) +
  geom_point() +
  labs(x = "Bill Depth (mm)", 
       y = "Bill Length (mm)", 
       title = "Palmer Penguins") +
* theme_bw()
```

]

]

---

## Themes

]

]

]

]

]

]
]

---

]

![](2-data-viz_files/figure-html/unnamed-chunk-70-1.png)
]

---

```r
?theme
```

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species)) +
  geom_point(size = 4) +
* facet_grid(.~species)
```

]

.right-panel[
<img src="2-data-viz_files/figure-html/unnamed-chunk-73-1.png" style="display: block; margin: auto;" />
]

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm,
           shape = species,
           color = species)) +
  geom_point(size = 4) +
* facet_grid(species~.)
```

]

.right-panel[
<img src="2-data-viz_files/figure-html/unnamed-chunk-75-1.png" style="display: block; margin: auto;" />
]

---

```r
ggplot(penguins,
       aes(x = bill_depth_mm,
           y = bill_length_mm)) +
  geom_point() +
* xlim(0, 30) +
* ylim(0,70)
```

]

]

---

## code style

[The tidyverse style guide](https://style.tidyverse.org/ggplot2.html) has the following convention for writing ggplot2 code.

The plus sign for adding layers `+` always has a space before it and is followed by a new line.

The new line is indented by two spaces. RStudio does this automatically for you.

---
class: middle

[Top Ten Dos and Don't for Charts and Graphs](https://guides.lib.uci.edu/datavis/do)

---

Check out [the ggplot flipbook](https://evamaerey.github.io/ggplot_flipbook/ggplot_flipbook_xaringan.html#1) for some inspiration. 
Find your favorite new function/feature. 
Share it with your neighbor.

---

## ggplot extensions

- [`patchwork`](https://patchwork.data-imaginist.com/) combining plots into a single plot
- [`gganimate`](https://gganimate.com/) animated graphics
- [`ggthemes`](https://rafalab.github.io/dsbook/ggplot2.html#add-on-packages) additional set of themes
- [`ggtext`](https://wilkelab.org/ggtext/) improved text rendering support for ggplot2

There are [more extensions](https://exts.ggplot2.tidyverse.org/gallery/)

---

## Detour: R Markdown chunk options

```{r, echo=TRUE, message=FALSE}
```
---

## (some) Chunk Options in R Markdown

<tr>

<td>echo = FALSE</td>
<td>hides the code</td>

</tr>

<tr>

<td>message = FALSE</td>
<td>hides messages</td>

</tr>

<tr>

<td>warning = FALSE</td>
<td>hides warning</td>

</tr>

<tr>

<td>error = TRUE</td>
<td>renders despite errors and displays the error</td>

</tr>

<tr>

<td>fig.cap = "Some figure caption"</td>
<td>creates a figure caption</td>

</tr>

<tr>

<td>fig.alt = "Some alternate text for figure"</td>
<td>creates alternate text for figures</td>

</tr>

</table>

---

## Schedule for the Day

__10:00 - 10:15 Introduction and Setup__  
__10:15 - 11:15 Introduction to Toolkit and Data Basics__  
__11:20 - 12:30 Data Visualization__  
1:00 - 1:45 Data Wrangling   
1:45 - 2:15 Packages and External Datasets
2:15 - 2:30 Wrap Up