The Art of R Programming

Slot "salary":

[1] 55000

Slot "union":

[1] TRUE

Note that the member variables are calledslots, referenced via the@sym-

bol. Here’s an example:

> joe@salary

[1] 55000

We can also use theslot()function, say, as another way to query Joe’s

salary:

> slot(joe,"salary")

[1] 55000

We can assign components similarly. Let’s give Joe a raise:

> joe@salary <- 65000

> joe

An object of class "employee"

Slot "name":

[1] "Joe"

Slot "salary":

[1] 65000

Slot "union":

[1] TRUE

Nah, he deserves a bigger raise that that:

> slot(joe,"salary") <- 88000

> joe

An object of class "employee"

Slot "name":

[1] "Joe"

Slot "salary":

[1] 88000

Slot "union":

[1] TRUE

224 Chapter 9