The Rust Programming Language — References and Borrowing — Slices

Grab a slice for yourself!

You can define a vector quite easily in Rust. But what if you want to reference just a portion of the vector without having to create a new copy of it? Slices come to the rescue. Slices are nothing but the references of a portion of a vector. Just like VectMetadata {} we get StructMetadata {}.

struct VectMetadata {
  first_elem_index: usize,
  length: usize,
  capacity: usize,
}

struct SliceMetadata {
  first_elem_index: usize,
  length: usize,
}

fn main() {
    let years: Vec<i32> = vec![2001, 2002, 2003, 2004];
    let slice = &nums[0..2];
}

The only difference between the metadata of a Vector and a Slice is slice does not have capacity. Slices can be a really nice way of referencing same piece of memory from heap and creating a new memory in the stack. We can make slices of Vectors or even strings if you a subset of chars. Slice does not own the elements, it just references them:

The type of years is Vec<i32> where as the type of slice is &[i32]. You can slice the strings as well.

fn main() {
    let years: Vec<i32> = vec![2001, 2002, 2003, 2004];
    let slice = &nums[0..2];
    let name = "hello world!";
    let name_slice: &str = name[0..2];
}

You can also get all the elements of a Vector or a string as a slice by using .as_slice() or .as_str() method.

I hope you enjoyed this article about the Slices on Vectors and Strings in Rust.

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