# R Presentation

Jeffery Russell
3-29-19

### Signin: bit.ly/ritlug-mar-29

### History

- Back in the day (1976) Bell Laboratories created the S statisticsl programming language
- People were sad because it was exclusively licensed by AT&T
- During the 90's a group of people developed a S replacement called R and it was liscensed under GNU

### Why use R

- Statistics and data analysis
- Machine learning
- Fast prototyping
- Creating graphs
- Writing research papers and reports
- Creating presentations (like this one)

### Embedding Code Output in a Document

    summary(cars)

         speed           dist
     Min.   : 4.0   Min.   :  2.00
     1st Qu.:12.0   1st Qu.: 26.00
     Median :15.0   Median : 36.00
     Mean   :15.4   Mean   : 42.98
     3rd Qu.:19.0   3rd Qu.: 56.00
     Max.   :25.0   Max.   :120.00

### Embedding Graphs in a Document

    plot(mtcars$wt, mtcars$mpg, main="Weight vs MPG", xlab = "weight", ylab="MPG")

### Syntax

- Syntax of R is C esk with its use of curly braces
- Variables are similar to python since it infers your data type used
- Type system is rather wierd, the base unit for everything is a vector– even integers

    if(TRUE)
    {
      print("Hello World")
    }

    [1] "Hello World"

### Syntax cont

### ML Example pt: 1

### ML Example pt: 2

### Super Cool ML Example pt: 3

    sc <- spark_connect(master = "local")

    iris_tbl <- sdf_copy_to(sc, iris, name = "iris_tbl", overwrite = TRUE)

    partitions <- iris_tbl %>%
      sdf_partition(training = 0.7, test = 0.3, seed = 1111)

    iris_training <- partitions$training
    iris_test <- partitions$test

    dt_model <- iris_training %>%
      ml_decision_tree(Species ~ .)

    pred <- ml_predict(dt_model, iris_test)

    ml_multiclass_classification_evaluator(pred)

    [1] 0.9451737

### Resources

- R Language Overview
- R Studio
- R 4 Data Science

### Demo/Questions?