Rust Tutorials

How to create an Empty Set in Rust

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How to create an Empty Set in Rust ?

Answer

To create an empty set in Rust, you can use the HashSet type from the standard library.

✐ Examples

1 Create Empty Set using HashSet

In this example,

We import the necessary HashSet module from the standard library by including the statement use std::collections::HashSet;.
We declare an empty HashSet named empty_set, specifying the type of elements it will hold.
The HashSet type in Rust provides constant-time average complexity for operations like insertions, deletions, and lookups.

Rust Program

use std::collections::HashSet;

fn main() {
    // Declare an empty set
    let mut empty_set: HashSet<i32> = HashSet::new();

    // empty_set is now ready to be used as an empty set

    // Example usage:
    // Add elements to the set
    empty_set.insert(5);

    // Remove elements from the set
    empty_set.remove(&5);

    // Check if an element is present in the set
    let contains_element = empty_set.contains(&5);

    println!("Is element 5 present in the set: {}", contains_element);
}

Output

Is element 5 present in the set: false

Summary

In this tutorial, we learned How to create an Empty Set in Rust language with well detailed examples.