session_01_speaker.Rmd

---
title: Session 1 — Speaker Notes
date: "July 18, 2018"
---

## Introduction

Using [slides](slides/session_01_slides.html)

1. Meet and greet
    - Group sharing
        - Name/Role
        - First computer
        - Wildest dreams
    - About me
1. Why R and the tidyverse?
    - What is R, what is the tidyverse
    - Pit of success
    - GUIs vs code
    - Code is text
    - Sharing, reading, copy paste, manipulate
1. Joining the community
    - Expectations
    - Coding myth
    - Meet the community
    
## Lay of the Land

Walk through open panes in plain RStudio

### Console

#### Calculator

```r
1 + 100

1 +

3 + 5 * 2

(3 + 5) * 2

(3 + (5 * (2 ^ 2))) # hard to read
3 + 5 * 2 ^ 2       # clear, if you remember the rules
3 + 5 * (2 ^ 2)     # if you forget some rules, this might help

2/10000 # scientific notation

5e3
```

#### Advanced Calculator

```r
sin(1)
log(1)
```

#### Comparing Things

```r
1 == 1
1 != 2
1 < 2
4 <= 5
4 > 5   # FALSE
10 >= 1
FALSE == F
TRUE == T
```

### Environment

Demonstrate how objecst are stored in your environment

```r
x <- 1/40
log(x)
x <- round(x, 1)
y <- x
```

### Script

Scripts hold code, demonstrate how to enter in file and how to run from file.

#### Variable Names

- Numbers, letters, underscores, periods
- Can't start with number
- Can use spaces but not recommended

```r
name.with.dots <- 3
nameWithCamelHumps <- 2
name_with_underscores <- 1
```

#### History

Previously run commands show up in the history.

### More syntax

#### Vectors

```r
c(1, 2)

c(1, 2, 3, 4, 5)

1:5

c(1, 2, 3) * 2

x <- seq(1, 10, by = 2)
x * 2
mean(x)
```

#### Strings or character

```r
word1 <- "Core"
word2 <- 'Data'     # " or '
word3 <- "Services"

c(word1, word2, word3)

cds <- paste(word1, word2, word3)

tolower(cds)
```

#### Vectors vs Lists

At this point, we've seen `integer`, `numeric`, `logical` and `character`.

```r
typeof(3.14)
typeof(1)      #<< double
typeof(1L)     #<< integer
typeof(TRUE)
typeof("apple")
```

Vectors can only have things of the same type

```r
c(2, 4, 6)
c(2, 4, 6L)
typeof(c(2, 4, 6L))

c(1L, "1")

c("a", TRUE)
```

Lists can have anything you want

```r
list("a", 1L, 3.14, 1:5, FALSE)

list("a", 1:5, c("a", 1:5))

list(1:5, c("a", "b", "c", "d", "e"))
```

### Data Frames

```r
data.frame(1:5, c("a", "b", "c", "d", "e"))

data.frame(x = 1:5, y = c("a", "b", "c", "d", "e"))
```

### Working directories

`getwd()` and `setwd()` set where your current session of R looks for files.

### RStudio Projects

- Organize your code and data together
- Treat input data as read-only inside a project
- Easy to switch "contexts"
- Restart from scratch often!
- Creating new projects
- Interactive vs Scripts
- create a project for this course

## Packages

- `install.packages()`
- `library()`
- `library(tidyverse)`
- `pkg::function()`

## Getting Help

- `?help` and `??help`
- tidyverse.org
- stackoverflow

## Intro data processing

Go back to the [session page](session_01.html#lets-process-some-data)

- tidyverse: readr and dplyr
- readr: read_csv
- dplyr: group_by, count, summarize, filter