01_Introduction.Rmd

# Introduction

**Learning objectives:**

**For the entire book:**

- Improve programming skills.
- Develop a deep understanding of the R language fundamentals.
- Understand what functional programming means.
- Understand object-oriented programming as applied in R.
- Understand metaprogramming while developing in R.

**For this chapter (includes the Welcome and Preface):**

- Recognize the differences between the 1st and 2nd edition of this book.
- Describe the overall structure of the book.
- Decide whether this book is right for you.

Books suggestions:

- [The Structure and Interpretation of Computer Programs (SICP)](https://mitp-content-server.mit.edu/books/content/sectbyfn/books_pres_0/6515/sicp.zip/full-text/book/book.html)
- [Concepts, Techniques and Models of Computer Programming](https://mitpress.mit.edu/books/concepts-techniques-and-models-computer-programming)
- [The Pragmatic Programmer](https://pragprog.com/titles/tpp20/the-pragmatic-programmer-20th-anniversary-edition/)

## What's new?

> "The [first edition](http://adv-r.had.co.nz) used base R functions almost exclusively, this version of the book expands into more advanced functions provided by other pakages."

> "Use of new packages, particularly rlang, which provides a clean interface to low-level data structures and operations."

```{r, echo=FALSE,out.width="49%",out.height="49%",fig.show='hold',fig.align='center', fig.cap="Twitter: `@hadleywickham` - 6 June 2019"}
knitr::include_graphics(c("images/01-hadley-image1.jpeg","images/01-hadley-image2.jpeg"))
```

## Overview of the book structure

* The book is composed of five sections. A step by step path towards mastering R techniques.
* The **Foundations** is the part in which the R components will be examined. It will help understanding how to use all the basics tools to deal with functions and structures.
* The **Functional programming** goes a little more in dept into programming with R, making functions of functions. Describing function factories and operators.
* The **Object-oriented programming** - OOP is a five chapter section, all about object oriented systems among S3, R6 and S4.
* The **Metaprogramming** section introduces you through the programming layers.
* Finally, the **Techniques** section is dedicated to finding and fixing bugs and improving performances.

### What this book is not

* This book is about the R programming language, not R as the data analysis tool. 
  * Other books cover this topic.
  * [R for Data Science](https://r4ds.had.co.nz/).
* We will not be discussing package development at length.
  * [R Packages](https://r-pkgs.org/).
* Some experience using R will be helpful.
  * I encourage all to participate, though.


### Organization of the book

```{r dia-lib,include=FALSE}
library(DiagrammeR)
```
<center>
```{r c00, echo=FALSE, fig.align='center', fig.dim="100%"}
DiagrammeR("
   graph TD
     A{Foundations}-->B(Functional programming)
     B-->C(Object-oriented programming)
     C-->D(Metaprogramming)
     D-->E(Techniques)
 ")
```
</center>

### Foundations

Six chapters to learn the foundational components of R. 
<center>
```{r c01, echo=FALSE, fig.align='center', fig.dim="100%"}
DiagrammeR("
   graph TD
     A{Foundations}-->B(Names and values)
     A-->C(Control flow)
     C-->E(Functions)
     B-->D(Vectors)
     D-->F(Subsetting)
     E-->G(Environment)
     G-->H(Conditions)
F-->H
 ")
```
</center>
The last chapter "conditions" describe errors, warnings, and messages.


### Functional programming

This part of the book is dedicated to functions: function factories and operators.

<center>
```{r c02,echo=FALSE,fig.align='center',fig.dim="100%"}
DiagrammeR("
   graph TD
     A{Functional programming}-->B(Functionals)
     B-->C(Function factories)
     B-->E(Function operators)
 ")
```
</center>

### Object-oriented programming


OOP is the most dense part of the book, as it mentions about systems which interact with R. 

<center>
```{r c03,echo=FALSE,fig.align='center',fig.dim="100%"}
DiagrammeR("
   graph TD
     A{Object-oriented programming}-->B(Base types)
     B-->C(S3)
     B-->E(R6)
     B-->D(S4)
     D-->F(Trade-offs)
     E-->F
     C-->F
")
```
</center>

### Metaprogramming

This is the part of the book where things are blended to the **Big Picture**. R is a versatile functional language that can be managed and assembled.

<center>
```{r c04,echo=FALSE,fig.align='center',fig.dim="100%"}
DiagrammeR("
   graph TD
     A{Metaprogramming}-->B(Big Picture)
     B-->C(Expressions)
     B-->E(Quasiquotation)
     B-->D(Evaluation)

     D-->F(Translating R code)
E-->F
C-->F

 ")
```
</center>


### Techniques

Finally, this is the last section of the book, where debugging is used to measure and improve performance. And how to improve performance by rewriting key functions in C++.

<center>
```{r c05,echo=FALSE,fig.align='center',fig.dim="100%"}
DiagrammeR("
   graph TD
     A{Techniques}-->B(Debugging)
     B-->C(Measuring performance)
     B-->E(Improving performance)
     C-->D(Rewriting R code in C++)
E-->D


 ")
```
</center>

## Resources

- [first edition](http://adv-r.had.co.nz) 
- [advanced-r-solutions](https://advanced-r-solutions.rbind.io/)


## Meeting Videos

### Cohort 1

(no video recorded)

### Cohort 2

`r knitr::include_url("https://www.youtube.com/embed/PCG52lU_YlA")`

### Cohort 3

`r knitr::include_url("https://www.youtube.com/embed/f6PuOnuZWBc")`

### Cohort 4

`r knitr::include_url("https://www.youtube.com/embed/qDaJvX-Mpls")`

### Cohort 5

`r knitr::include_url("https://www.youtube.com/embed/BvmiQlWOP5o")`

### Cohort 6

`r knitr::include_url("https://www.youtube.com/embed/dH72riiXrVI")`

<details>
<summary> Meeting chat log </summary>

```
00:14:40	SriRam:	From Toronto, Civil Engineer. I use R for infrastructure planning/ GIS. Here coz of the ping 😄 , was not ready with a good computer with mic/audio !
00:15:20	SriRam:	I was with Ryan, Federica on other courses
00:23:21	SriRam:	I think the only caution is about Copyright issues
00:31:32	Ryan Metcalf:	Citation, giving credit back to source. Great comment SriRam.
00:34:33	SriRam:	one = one, in my opinion
00:41:53	Ryan Metcalf:	https://docs.google.com/spreadsheets/d/1_WFY82UxAdvP4GUdZ2luh15quwdO1n0Km3Q0tfYuqvc/edit#gid=0
00:48:35	Arthur Shaw:	The README has a nice step-by-step process at the bottom: https://github.com/r4ds/bookclub-advr#how-to-present. I've not done this myself yet, but it looks fairly straightforward.
00:54:13	lucus w:	Thanks Ryan. Probably {usethis} will be easier. It looks straight forward
01:00:02	Moria W.:	Thank you for sharing that. This has been good!
01:00:08	Vaibhav Janve:	Thank you
01:00:44	Federica Gazzelloni:	hi SriRam we are going..
```
</details>

### Cohort 7

`r knitr::include_url("https://www.youtube.com/embed/vfTg6upHvO4")`
`r knitr::include_url("https://www.youtube.com/embed/3wRyE6-3OKQ")`

<details>

<summary>Meeting chat log</summary>
```
00:20:42	collinberke:	https://rich-iannone.github.io/pointblank/
00:27:36	Ryan Honomichl:	brb
00:37:05	collinberke:	https://rstudio.github.io/renv/articles/renv.html
00:51:52	Ryan Honomichl:	gotta sign off I'll be ready to lead chapter 2 next week!
00:52:43	collinberke:	https://r4ds.had.co.nz/iteration.html
00:59:44	collinberke:	https://mastering-shiny.org/action-tidy.html
01:00:12	collinberke:	https://dplyr.tidyverse.org/articles/programming.html
01:05:02	collinberke:	https://usethis.r-lib.org/reference/create_from_github.html
01:05:53	collinberke:	https://github.com/r4ds/bookclub-advr
01:06:28	Ron:	I gotta run ,  fun conversation, and nice to meet you Matthew !
```
</details>