set

Set - In mathematics, a set is a well-defined collection of distinct objects. Notation often uses curly braces: . Operations like intersection, union, and subset relationships form the basis of set theory.

Key points:

• No repeated elements: sets ignore duplicates.
• Can contain any type of object, even other sets.

R demonstration:

library(data.table)
 
A <- c(1,2,3)
B <- c(3,4,5)
intersect(A,B)

## [1] 3

union(A,B)

## [1] 1 2 3 4 5