Menu
How do I remove the unused_variables warning from the following code?
pub enum Foo {
Bar {
a: i32,
b: i32,
c: i32,
},
Baz,
}
fn main() {
let myfoo = Foo::Bar { a: 1, b: 2, c: 3 };
let x: i32 = match myfoo {
Foo::Bar { a, b, c } => b * b,
Foo::Baz => -1,
};
assert_eq!(x, 4);
}
I know I can ignore struct members after a certain point with:
Foo::Bar { a, .. } => // do stuff with 'a'
But I can't find documentation anywhere that explains how to ignore individual struct members.
Code on Rust Playground
304
Adding data to enum variantsCreated a new instance of the enum and assigned it to a variable. Put that variable in a match statement. Destructured the contents of each enum variant into a variable within the match statement.
Patterns are a special syntax in Rust for matching against the structure of types, both complex and simple. Using patterns in conjunction with match expressions and other constructs gives you more control over a program's control flow.
structs can be used to model cars and define state. methods and associated functions can be used to specify their behaviour. enums can be used to specify range of allowed values for a custom data type. traits can be used to describe shared behaviours across user-defined data types.
An enum in Rust is a type that represents data that is one of several possible variants. Each variant in the enum can optionally have data associated with it: #![allow(unused_variables)] fn main() { enum Message { Quit, ChangeColor(i32, i32, i32), Move { x: i32, y: i32 }, Write(String), }
I know I can ignore struct members after a certain point with:
The .. is not positional. It just means "all the other fields":
Foo::Bar { b, .. } => b * b,
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
