Page 28 - Applied Statistics with R

28 CHAPTER 3. DATA AND PROGRAMMING

x[x > 3]

## [1] 5 7 8 9

x[x != 3]

## [1] 1 5 7 8 9

• TODO: coercion

sum(x > 3)

## [1] 4

as.numeric(x > 3)

## [1] 0 0 1 1 1 1

Here we see that using the sum() function on a vector of logical TRUE and FALSE
values that is the result of x > 3 results in a numeric result. R is first auto-
matically coercing the logical to numeric where TRUE is 1 and FALSE is 0. This
coercion from logical to numeric happens for most mathematical operations.

which(x > 3)

## [1] 3 4 5 6

x[which(x > 3)]

## [1] 5 7 8 9

max(x)

## [1] 9

which(x == max(x))

## [1] 6