Booleans and George Boole’s 200th Birthday!

Booleans are vectors in R and other programming languages, which can take the logical form TRUE or FALSE. For example, let’s compare the numbers 24 and 100, as we did in slide 22 of R course - Lecture 1:

We create a numerical vector of length one (because there is only one element in it), called x, which has the value 24:

x <- 24

We compare x (whose value is 24) against another value… let’s say, 100:

• Hey R, is x greater than 100?

x > 100

[1] FALSE

R says it’s FALSE because 24 is not greater than 100.

• Is x smaller than 100?

x < 100

[1] TRUE

• Is x not equal to 100? (In R, ‘not equal to’ is written with an exclamation mark followed by an equal sign):

x != 100

[1] TRUE

• Is x exactly equal to 100? (In R, ‘exactly equal to’ is written with two equal signs):

x == 100

[1] FALSE

The guy who pioneered this system in the mid 1800s was George Boole, and that’s why we call these logical expressions booleans. Google made a very nice doodle today to commemorate this date:

You may find the permanent link for this doodle here