Introduction_to_R.Rmd

---
title: "Introduction to R"
author: "Chunlei Ge"
date: '2023-01-24'
output:
  pdf_document:
    toc: yes
    fig_height: 6
    fig_width: 10
    number_sections: yes
  html_document:
       theme: united
       toc: true
       toc_float: no
       number_sections: true
       highlight: tango
       fig_width: 10
       fig_height: 8
editor_options: 
  chunk_output_type: console
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

# Learning objectives

-   How to install R and Rstudio

-   How to load an R package

-   How to use RStudio cloud server

-   How to update them

-   How to run some simple calculation

# R and Rstudio 

## Download and install R

### Windows

Visit [\textcolor{blue}{R Project}](https://www.r-project.org/) to learn about R versions
Download and install R from your preferred CRAN mirror [\textcolor{blue}{here}](https://cran.r-project.org/mirrors.html)
Choose “0-Cloud” or a mirror site near you

### Mac

Check that your macOS system is up-to-date

Download and install R from  [\textcolor{blue}{R Archive Network}](https://cran.r-project.org/)

### Linux

Download R for Linux <https://mirror.rcg.sfu.ca/mirror/CRAN/>

## Download and install R studio IDE (Windows and Mac)

Download and install R Studio from [\textcolor{blue}{here}](https://www.rstudio.com/products/rstudio/download/#download)

## R Markdown

R Markdown is a format for writing reproducible, dynamic reports with R. 

R Markdown document can help us generate PDF, HTML, and other types of output with R code, results, and raw LaTeX.

(This pdf file <Introduction_to_R.pdf> is the output of Rmarkdown file <Introduction_to_R.Rmd>.

Feel free to open and edit it after you install Rstudio in your computer or use it as the template of your first report)

Learn more at https://rmarkdown.rstudio.com/

And a quick way to familiar with R Markdown https://www.rstudio.com/wp-content/uploads/2015/02/rmarkdown-cheatsheet.pdf 

Some more about R studio: https://www.rstudio.com/resources/cheatsheets/

## Load R package

use function: $install.packages()$ to installing a package installing a Java Version : <https://www.java.com/en/download/>

```{r eval=FALSE}
install.packages("MASS")
install.packages("rJava") 
install.packages("RWeka")
```

Help

```{r}
help (pi)
?pi
# the mathematical functions ...
?Arithmetic
?abs
?log
?round
?sin
?Special
```

\

Loading an R package

```{r}
library(MASS)
library(rJava)
library(RWeka)
```

## How to use RStudio cloud

<https://rstudio.cloud/>

## How to update

### Updating R

Windows\
First Install the $installr$ package if you don't have it

```{r}
# installing/loading the package:
if(!require(installr)) {
  install.packages("installr"); 
  require(installr)
} #load / install+load installr
```

Now call $updateR()$ function to call update

```{r eval=FALSE}
updateR()
```

\

macOS\
One Mac you need to go to the CRAN website to install the newer package installer.

### Updating RStudio

Updating RStudio is easy, just go to $Help$ \> $Check\ for\ Updates$ to install newer version.

### Updating R package

Updating out of date package that were installed with $install.packages()$is easy with the $update.packages()$ function.

```{r eval=FALSE}
update.packages("MASS")
```

# Simple calculation

```{r}
x <- c(67,67,77,62,69.84,74.168,29.5,81.8,71,71,74.8)
y <- c(170,176,172,183,167.64,175.26,165.1,177.8,170,178,176)

y^2
y+2
y/2
x+2
x*x
2*x
x^2
log(x)
```

# Reference

Data Analysis in R. https://ubc-library-rc.github.io/data-analysis-r/

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 \center{**
 Keep Calm and Have a Cup of Tea**}
![tea](C:/Users/ivyge/Downloads/tea.png)
 \center{image: https://www.expertreviews.co.uk/food-drink/1415799/best-green-tea}