Exercise

# Timings - pre-allocation

In the previous exercise, growing the vector took around 2 seconds.
How long does it take when we pre-allocate the vector? The `pre_allocate()`

function is defined below.

```
n <- 30000
# Fast code
pre_allocate <- function(n) {
x <- numeric(n) # Pre-allocate
for(i in 1:n)
x[i] <- rnorm(1)
x
}
```

Instructions

**100 XP**

The `pre_allocate()`

function is available in your workspace.

- Using
`system.time()`

, find how long it takes to run`pre_allocate(n)`

. Use the`<-`

trick to store the result in the object`res_allocate`

.