Data Types
Scalar Data Types
Rust has several categories of primitive types: integers, floating-point numbers, Booleans, unicode characters, 'Unit', and 'Never'.
| Type Family | Types | Examples |
|---|---|---|
| Signed Integers | i8⮳, i16⮳, i32⮳, i64⮳, i128⮳, isize⮳. | -8i8, -32i32. |
| Unsigned Integers | u8⮳, u16⮳, u32⮳, u64⮳, u128⮳, usize⮳. | 6u8. |
| Floating point | f32⮳, f64⮳. | 0.15. |
| Boolean | bool⮳. | true, false. |
| Unicode Character | char⮳ | let z: char = 'ℤ'; |
| Unit | unit⮳. | The () type (aka 'void' in other languages) has exactly one value (), and is used when there is no other meaningful value that could be returned. |
| Never | never⮳. | ! represents the type of computations which never resolve to any value at all. For example, the exit function fn exit(code: i32) -> ! exits the process without ever returning, and so returns !. |
usize⮳ and isize⮳ are 32 or 64 bits, depending on the architecture of the computer.
The following illustrates the various scalar data types:
Compound Data Types: Tuples and Arrays
Compound types can group multiple values into one type. Rust has two primitive compound types: tuples and arrays.
| Type | Examples |
|---|---|
| Tuples | let tup: (i32, f64, u8) = (500, 6.4, 1);. Access via let five_hundred = x.0;. Destructuring via let (x, y, z) = tup;. |
| Arrays | let a: [i32; 5] = [1, 2, 3, 4, 5]; allocated on the stack. Access via let first = a[0];. |
Both are fixed length. A Vector is a similar collection type provided by the standard library that is allowed to grow or shrink in size.
The following provides examples of tuples and arrays:
Type Aliases
Use the type keyword to declare type aliases: type Kilometers = i32;.
Related Topics
See also:
- Enums.
- Option.
- Result.
- Slices.
- Strings.
- Structs.
- Vectors.
- Data Structures.