元组是不同类型的值的集合。 元组使用括号构造 (), 每个元组本身是类型签名值 (T1, T2, ...), 这里 T1, T2 是其成员的类型。 函数可以使用元组返回多个值，元组可以包含任意数量的值。
| // Tuples can be used as function arguments and as return values |
| fn reverse(pair: (i32, bool)) -> (bool, i32) { |
| // `let` can be used to bind the members of a tuple to variables |
| let (integer, boolean) = pair; |
| (boolean, integer) |
| } |
| fn main() { |
| // A tuple with a bunch of different types |
| let long_tuple = (1u8, 2u16, 3u32, 4u64, |
| -1i8, -2i16, -3i32, -4i64, |
| 0.1f32, 0.2f64, |
| 'a', true); |
| // Values can be extracted from the tuple using tuple indexing |
| println!("long tuple first value: {}", long_tuple.0); |
| println!("long tuple second value: {}", long_tuple.1); |
| // Tuples can be tuple members |
| let tuple_of_tuples = ((1u8, 2u16, 2u32), (4u64, -1i8), -2i16); |
| // Tuples are printable |
| println!("tuple of tuples: {:?}", tuple_of_tuples); |
| let pair = (1, true); |
| println!("pair is {:?}", pair); |
| println!("the reversed pair is {:?}", reverse(pair)); |
| // To create one element tuples, the comma is required to tell them apart |
| // from a literal surrounded by parentheses |
| println!("one element tuple: {:?}", (5u32,)); |
| println!("just an integer: {:?}", (5u32)); |
| } |
