How to sort a Vec

Collections
2026-04-17T16:32:01+00:00
You can sort a `Vec` in place using the `.sort()` method for simple types or `.sort_by_key()` for custom ordering, while `.sorted()` from the `itertools` crate or `.into_iter().sorted()` provides a non-destructive alternative.

You can sort a Vec in place using the .sort() method for simple types or .sort_by_key() for custom ordering, while .sorted() from the itertools crate or .into_iter().sorted() provides a non-destructive alternative. For most cases, mutating the original vector with .sort() is the most efficient approach as it avoids allocation.

Here is how to sort a vector of integers in ascending order in place:

fn main() {
    let mut numbers = vec![3, 1, 4, 1, 5, 9, 2, 6];
    
    // Sorts the vector in place
    numbers.sort();
    
    println!("{:?}", numbers); 
    // Output: [1, 1, 2, 3, 4, 5, 6, 9]
}

When dealing with complex types or needing custom logic (like sorting by a specific field or descending order), use .sort_by_key() or .sort_by(). For example, sorting a vector of structs by a field:

#[derive(Debug)]
struct User {
    name: String,
    age: u32,
}

fn main() {
    let mut users = vec![
        User { name: "Alice".to_string(), age: 30 },
        User { name: "Bob".to_string(), age: 25 },
        User { name: "Charlie".to_string(), age: 35 },
    ];

    // Sort by age in ascending order
    users.sort_by_key(|u| u.age);

    // Sort by name in descending order
    // users.sort_by(|a, b| b.name.cmp(&a.name));

    println!("{:?}", users);
}

If you need to keep the original vector unchanged, you must clone it before sorting or use an iterator-based approach. Note that the standard library does not provide a direct .sorted() method on Vec that returns a new vector without cloning; you typically chain .clone() or use the itertools crate for a more ergonomic .sorted() method.

fn main() {
    let numbers = vec![3, 1, 4, 1, 5];
    
    // Clone first, then sort in place
    let sorted = {
        let mut temp = numbers.clone();
        temp.sort();
        temp
    };
    
    println!("Original: {:?}", numbers);
    println!("Sorted:   {:?}", sorted);
}

Remember that .sort() requires the elements to implement the Ord trait, while .sort_by() and .sort_by_key() allow you to define custom comparison logic for types that only implement PartialOrd or require specific extraction logic.