RUST 04 — Vector & Strings

Learn Rust and develop in a safer way.

These are the notes taken while I was learning Rust on online course made by ZeroToMastery Academy.

💧What we will learn

• vector
• strings

🔥Good Resources

Playground | Replit

ZeroToMastery | RUST

Source Code in Github

⚡Vector

• Hold multiple pieces of data(same type)
• Can add, remove and traverse the entries
• use for…in to iterate

🔸Data Structure

let my_numbers = vec![10, 20, 30, 40];

or

fn main() {
    let mut my_nums = Vec::new();
    my_nums.push(1);
    my_nums.push(2);
    my_nums.push(3);
    my_nums.pop();
    my_nums.len(); // 2

    let item_1 = my_nums[1];

}

🔸Example

fn main() {
    let my_numbers = vec![10, 20, 30, 40];
    for num in &my_numbers {
        match num {
            30 => println!("thirty"),
            _ => println!("{:?}", num),
        }
    }

    println!("number of elements = {:?}", my_numbers.len());
}

/*
10
20
thirty
40
number of elements = 4
*/

⚡strings

• 2 commonly used types of strings
  - String ( used mostly )
  - &str ( pass to function )

fn print_it(data: &str) {
    println!("{:?}", data);
}

fn main() {
    print_it("A string slice");
    let owned_string = "owned string".to_owned();
    let another_string = String::from("another");

    print_it(&owned_string);
    print_it(&another_string);
}

/*
"A string slice"
"owned string"
"another"
*/

🔸Example #02

struct LineItem {
    name: String,
    count: i32,
}
fn print_name(name: &str) {
    println!("name: {:?}", name);
}

fn main() {
    let receipt = vec![
        LineItem {
            name: "Apple".to_owned(),
            count: 1,
        },
        LineItem {
            name: String::from("Citrus"),
            count: 3,
        },
    ];

    for item in receipt {
        print_name(&item.name);
        println!("count: {:?}", item.count);
    }
}
/*
name: "Apple"
count: 1
name: "Citrus"
count: 3
*/

🔸Example #03

struct Person {
    name: String,
    fav_color: String,
    age: i32,
}

fn print(data: &str) {
    println!("{:?}", data);
}

fn main() {
    let people = vec![
        Person {
            name: String::from("George"),
            fav_color: String::from("green"),
            age: 7,
        },
        Person {
            name: String::from("Anna"),
            fav_color: String::from("purple"),
            age: 9,
        },
        Person {
            name: String::from("Katie"),
            fav_color: String::from("blue"),
            age: 14,
        },
    ];

    for person in people {
        if person.age <= 10 {
            print(&person.name);
            print(&person.fav_color);
        }
    }
}

/*
"George"
"green"
"Anna"
"purple"
*/