Understand how a logical vector can be used as an address So

Understand how a logical vector can be used as an address.

In R language we can also use logical vectors as parameter for the index function.

When it is used a vector with values that make logical vector true are obtained (i.e whether logical condition is satisfied or not)

Example :
> x <- c(4, 5, 1, NA, 2)

> x[x > 3]

[1] 4 5 NA

Here x>3 is a logical vector

Example 2

> a <- c(1,2,3,4,5)

> b <- c(TRUE,FALSE,FALSE,TRUE,FALSE)

> a[b]

[1] 1 4

> max(a[b])

[1] 4

> sum(a[b])

[1] 5

Here b is a logical vector to address which elements of \"a\" are available