Slices are pointers to the actual data. They are passed by reference to functions, which is also known as borrowing.
For example, slices can be used to fetch a portion of a string value. A sliced string is a pointer to the actual string object. Therefore, we need to specify the starting and ending index of a String. Index starts from 0 just like arrays.
```
fn main() {
let n1 = "Tutorials".to_string();
println!("length of string is {}",n1.len());
let c1 = &n1[4..9];
// fetches characters at 4,5,6,7, and 8 indexes
println!("{}",c1);
}
```
The &mut keyword can be used to mark a slice as mutable.