1. Using RStudio

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ggplot2

The ggplot2 package providse powerful data visualization. To install it, run the following in the RStudio console:

install.packages("ggplot2")

Once installed, load the package in each script with:

library(ggplot2)

Note that in RStudio’s Source pane, pressing Ctrl+Enter (or clicking Run) executes only the current line. Code runs line by line.

2. R Language Basics

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Data Types

Basic Types

In R, variables are assigned without explicit type declarations. For example, value <- 123 stores 123 in value. The same variable can later hold a different type.

R has six atomic data types, summarized below. Use print(class(x)) to check the type of x.

Data Type	Examples
Raw	See explanation
Logical	TRUE, FALSE
Integer	2L, 0L
Numeric	12.3, 123
Complex	3 + 2i
Character	'a', "good", "TRUE", '23.4'

The Raw type holds bytes. For instance:

rawData <- charToRaw("Hi")

stores "Hi" as the raw bytes 48 69.

Complex numbers must include the imaginary unit i explicitly, e.g., 3+1i. Omitting the numeric coefficient (3+i) causes an error.

Vectors

Combine multiple values into a vector with c():

vec <- c(3L, 5+2i, TRUE, "hello", 2.5)
print(vec)

Output:

[1] "3"     "5+2i"  "TRUE"  "hello" "2.5"  

All elements are coerced to the same type. When mixed, the priority order is Raw < Logical < Integer < Numeric < Complex < Character. Thus class(vec) returns "character".

Lists

A list can contain elements of any type, including other lists.

baseList <- list(10, 20, 30)
combinedList <- list(c(7, 8, 9), 3.14, sqrt, baseList, list(100, 200))
print(combinedList)

[[2]] [1] 3.14

[[3]] function (x) .Primitive("sqrt")

[[4]] [[4]][[1]] [1] 10

[[4]][[2]] [1] 20

[[4]][[3]] [1] 30

[[5]] [[5]][[1]] [1] 100

[[5]][[2]] [1] 200

 </details>Lists can be nested self-referentially, but they capture the state at assignment time:

 <details> <summary>Click to view code</summary> ```
> myList <- list(5)
> myList <- list(10, myList)
> print(myList)
[[1]]
[1] 10

[[2]]
[[2]][[1]]
[1] 5

> myList <- list(10, myList)
> print(myList)
[[1]]
[1] 10

[[2]]
[[2]][[1]]
[1] 10

[[2]][[2]]
[[2]][[2]][[1]]
[1] 5

Use the matrix() function to create a matrix:

mat <- matrix(1:6, nrow = 2, ncol = 3, byrow = TRUE)
print(mat)

The resulting 2×3 matrix is filled by row with 1,2,3 in the first row and 4,5,6 in the second.