match

_

通配符, 如果我们只想关心1,3,5,7, 其他的通过通配符来解决

let some_u8_value = 0u8; match some_u8_value {
    1 => println!("one"),
    3 => println!("three"),
    5 => println!("five"),
    7 => println!("seven"),
    _ => (),
}

if let

let some_u8_value = Some(0u8);
if let Some(3) = some_u8_value {
    println!("three");
}