Expand description
Control flow based on pattern matching.
match
can be used to run code conditionally. Every pattern must
be handled exhaustively either explicitly or by using wildcards like
_
in the match
. Since match
is an expression, values can also be
returned.
let opt = Option::None::<usize>;
let x = match opt {
Some(int) => int,
None => 10,
};
assert_eq!(x, 10);
let a_number = Option::Some(10);
match a_number {
Some(x) if x <= 5 => println!("0 to 5 num = {x}"),
Some(x @ 6..=10) => println!("6 to 10 num = {x}"),
None => panic!(),
// all other numbers
_ => panic!(),
}
Runmatch
can be used to gain access to the inner members of an enum
and use them directly.
enum Outer {
Double(Option<u8>, Option<String>),
Single(Option<u8>),
Empty
}
let get_inner = Outer::Double(None, Some(String::new()));
match get_inner {
Outer::Double(None, Some(st)) => println!("{st}"),
Outer::Single(opt) => println!("{opt:?}"),
_ => panic!(),
}
RunFor more information on match
and matching in general, see the Reference.