How to Check If &Str Contains Enum In Rust?

To check if a &str contains an enum in Rust, you can use pattern matching to match the enum variant with the string. You can create a function that takes a &str and checks if it matches the enum variant using a match statement. If the enum is found in the string, return true, otherwise return false. Here is an example code snippet:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22

enum MyEnum {
    Variant1,
    Variant2,
}

fn contains_enum(input: &str) -> bool {
    match input {
        "Variant1" => true,
        "Variant2" => true,
        _ => false,
    }
}

fn main() {
    let text = "Some text with MyEnum::Variant1";
    
    if contains_enum(text) {
        println!("Contains the enum variant");
    } else {
        println!("Does not contain the enum variant");
    }
}

In this example, the function contains_enum checks if the input string contains any of the enum variants Variant1 or Variant2. You can expand the match statement to include all enum variants and update the logic as needed for your specific use case.

What is &str in rust?

&str in Rust is a reference to a string slice, which is a contiguous sequence of UTF-8 encoded characters in memory. It is a borrowed type, meaning it does not own the data it references, but instead points to the memory location where the string is stored. This allows for efficient copying and manipulation of strings without unnecessary memory allocations.&str is commonly used to represent string literals, string slices, and borrowed strings in Rust programs.

What is the syntax for defining an enum in rust?

The syntax for defining an enum in Rust is as follows:

1
2
3
4
5
6
7
8
9

enum MyEnum {
    Variant1,
    Variant2,
    Variant3(i32),         // Enum variant with associated data
    Variant4 {             // Enum variant as a struct
        field1: i32,
        field2: String,
    },
}

How to use pattern matching with enums in rust?

Pattern matching with enums in Rust allows you to easily handle different cases or variants of an enum by using match expressions. Here's how you can use pattern matching with enums in Rust:

1. Define an enum with multiple variants:

1
2
3
4
5

enum Shape {
    Circle(u32),
    Rectangle(u32, u32),
    Triangle(u32, u32, u32),
}

1. Use match expressions to handle each variant:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20

fn calculate_area(shape: Shape) -> u32 {
    match shape {
        Shape::Circle(radius) => 3 * radius * radius,
        Shape::Rectangle(width, height) => width * height,
        Shape::Triangle(side1, side2, side3) => {
            let s = (side1 + side2 + side3) / 2;
            (s * (s - side1) * (s - side2) * (s - side3)).sqrt() as u32
        }
    }
}

fn main() {
    let circle = Shape::Circle(5);
    let rectangle = Shape::Rectangle(3, 4);
    let triangle = Shape::Triangle(3, 4, 5);

    println!("Area of circle: {}", calculate_area(circle));
    println!("Area of rectangle: {}", calculate_area(rectangle));
    println!("Area of triangle: {}", calculate_area(triangle));
}

In this example, the calculate_area function uses a match expression to handle each variant of the Shape enum and calculate the area accordingly.

1. Run the code and see the output:

1
2
3

Area of circle: 75
Area of rectangle: 12
Area of triangle: 6

By using pattern matching with enums in Rust, you can easily handle different cases or variants of an enum and perform specific actions based on each case.