rust数据类型

rust数据类型支持primitive和compound类型，见下图

image.png

primitive类型

#![feature(core_intrinsics)]
fn print_type_of(_: T) {
    println!("{}", unsafe { std::intrinsics::type_name::() });
}

fn main() {
    println!("Hello, world!");
    let logical: bool = true;
    print_type_of(logical);
    
    let mut inferred_type = 12;
    print_type_of(inferred_type);
    
    inferred_type = 4294967296i64;
    print_type_of(inferred_type);
    
    let t = "a";
    print_type_of(t);
    
    let c = 'a';
    print_type_of(c);
   
}

compound数据类型

#![feature(core_intrinsics)]
fn print_type_of(_: T) {
    println!("{}", unsafe { std::intrinsics::type_name::() });
}

fn main() {
   
    let v = [1,2,3];
    print_type_of(v);
    
    let q:[i64; 3] = [1, 2, 3];
    print_type_of(q);
    
    let x: (i32, f64, u8) = (500, 6.4, 1);
    print_type_of(x);
    
    println!("{}", x.0);
    println!("{}", x.2);
    
    let a = [3; 5];
    print_type_of(a);
    
  //单元结构体
    struct Empty;
    let e = Empty;
    print_type_of(e);
    
    // 元组结构体
    struct TT(i32, i32, i32);
    let col = TT(0, 2, 4);
    print_type_of(col);
    
    // 具名结构体
    struct People {
        name: &'static str,
        qender: i32,
    }
    let pe = People{name:"tt", qender:3};
    print_type_of(pe);
    
    enum Number {
        Zero,
        One,
        Two,
    }
    let n = Number::One;
    print_type_of(n)
}

collections

参见https://doc.rust-lang.org/std/index.html#containers-and-collections，这里定义了collections的几个关键元素
The option and result modules define optional and error-handling types, Option and Result. The iter module defines Rust’s iterator trait, Iterator, which works with the for loop to access collections.

其中有几个基本元素需要注意定义

pub enum Option {
    None,
    Some(T),
}

enum Result {
   Ok(T),
   Err(E),
}

// iterator有70个左右的定义
pub trait Iterator {
    type Item;
Show 70 methods}

collections包括：

• Sequences: Vec, VecDeque, LinkedList
• Maps: HashMap, BTreeMap
• Sets: HashSet, BTreeSet
• Misc: BinaryHeap

列举几个例子

vec

参考 https://doc.rust-lang.org/std/vec/struct.Vec.html#

fn main() {
    println!("Hello, world!");
    
    let mut vec = Vec::new();
    vec.push(1);
    vec.push(2);
    
    println!("{}", vec.len());
    let p = vec.pop();
    if (p.is_some()) {
        println!("{}", p.unwrap());
    }
}

HashMap

use std::collections::HashMap;

fn main() {
    let mut map = HashMap::new();
    map.insert("a", 1);
    map.insert("b", 2);
    map.insert("c", 3);
    
    for (key, val) in map.iter() {
        println!("key: {} val: {}", key, val);
    }
}

小结

rust的数据类型还是比较丰富，融合了面向对象、函数式各种语言范式的长处。