Vector Size in Rust in Rust

We can get the size of a Vec using the .len() method:

let mut our_array = vec![50, 40, 30];

// Printing the size:
println!("{}", our_array.len()); // Output: 3

// Changing the vector:
our_array.pop();

// Printing the new size:
println!("{}", our_array.len()); // Output: 2

Using the size

We can use the size to access items from the end of a vector.

Because vectors are 0-indexed, the index of the last item is size - 1:

let our_array = vec![50, 40, 30];

let size = our_array.len();

// Printing the last item:
println!("{}", our_array[size - 1]); // Output: 30

// Printing the second to last item:
println!("{}", our_array[size - 2]); // Output: 40

Assignment
Follow the Coding Tutorial and let's play with some arrays.

Hint
Look at the examples above if you get stuck.