How do I match enum values with an integer?

by

You can derive FromPrimitive. Using Rust 2018 simplified imports syntax:

use num_derive::FromPrimitive;    
use num_traits::FromPrimitive;

#[derive(FromPrimitive)]
enum MyEnum {
    A = 1,
    B,
    C,
}

fn main() {
    let x = 2;

    match FromPrimitive::from_i32(x) {
        Some(MyEnum::A) => println!("Got A"),
        Some(MyEnum::B) => println!("Got B"),
        Some(MyEnum::C) => println!("Got C"),
        None            => println!("Couldn't convert {}", x),
    }
}

In your Cargo.toml:

[dependencies]
num-traits = "0.2"
num-derive = "0.2"

More details in num-derive crate, see esp. sample uses in tests.

More Related Contents:

  1. What is the correct way to return an Iterator (or any other trait)?
  2. How to transform fields during deserialization using Serde?
  3. Temporarily move out of borrowed content
  4. Initialize a large, fixed-size array with non-Copy types
  5. How do I return an instance of a trait from a method?
  6. “borrowed value does not live long enough” seems to blame the wrong thing
  7. Is it possible to make a type only movable and not copyable?
  8. How to use struct self in member method closure
  9. How do I call a function through a member variable?
  10. How do you pass a Rust function as a parameter?
  11. How do I implement a trait with a generic method?
  12. How do I use conditional compilation with `cfg` and Cargo?
  13. When I can use either Cell or RefCell, which should I choose?
  14. Return an async function from a function in Rust
  15. How to implement `serde::Serialize` for a boxed trait object?
  16. Borrow two mutable values from the same HashMap
  17. Can I take a byte array and deserialize it into a struct?
  18. How do I create a Rust callback function to pass to a FFI function?
  19. Why does a lazy-static value claim to not implement a trait that it clearly implements?
  20. How do I convert a usize to a u32 using TryFrom?
  21. Borrow pointer errors recursively traversing tree [duplicate]
  22. How can I borrow from a HashMap to read and write at the same time?
  23. What is the difference between `|_| async move {}` and `async move |_| {}`
  24. Cannot use moved BufReader after for loop with bufreader.lines()
  25. Expected closure, found a different closure
  26. How can I iterate on an Option?
  27. How does the Rust compiler know `Cell` has internal mutability?
  28. Creating Diesel.rs queries with a dynamic number of .and()’s
  29. How do I match based on a dynamic variable?
  30. How to match trait implementors

Leave a Comment