1、示例一:获取 Vector 中的元素 代码语言:javascript 复制 fnget_element(vector:Vec<i32>,index:usize)->Option<i32>{ifindex<vector.len(){Some(vector[index])}else{None}}fnmain(){letvector=vec![1,2,3,4,5];letindex=3;matchget_element(vector,index){Some(value)=>println!("Element at inde...
fn get_element(vector: Vec<i32>, index: usize) -> Option<i32> { if index < vector.len() { Some(vector[index]) } else { None } } fn main() { let vector = vec![1, 2, 3, 4, 5]; let index = 3; match get_element(vector, index) { Some(value) => println!("Element at...
•读取 vector 的元素:使用 &[index] 返回一个引用, 或者使用 get 方法以索引作为参数来返回一个 Option<&T>。 fn main() { let v = vec![1, 2, 3, 4, 5]; let third: &i32 = &v[2]; println!("The third element is {}", third); match v.get(2) { Some(third) => println!("...
first element of a vector is :20 Second element of a vector is :30 Third element of a vector is :40 Fourth element of a vector is :50 访问向量元素的第二种方法是使用get(index)方法,将vector的索引作为参数传递,并返回Option <&t>类型的值。 看下面一个示例代码 - fn value(n:Option<&i32>...
读取vector 的元素 有两种方法引用 vector 中储存的值:通过索引或使用get方法。 letv=vec![1,2,3,4,5];letthird:&i32=&v[2];// 使用索引值来获取值Tprintln!("The third element is {third}");letthird:Option<&i32>=v.get(2);// get(索引值),得到Option<&T>matchthird{Some(third)=>println!
有两种方法引用 vector 中储存的值:通过索引或使用 get 方法。 letv=vec![1,2,3,4,5];letthird:&i32=&v[2];println!("Thethird element is{third}");letthird:Option<&i32>=v.get(2);matchthird{Some(third)=>println!("Thethird element is{third}"),None=>println!("Thereis no third element...
("v,{:?}",v); // read vector let third: &i32 = &v[2]; println!("The third element is {}", third); match v.get(2) { Some(third) => println!("The third element is {}", third), None => println!("There is no third element."), } } 我们使用索引值 2 来获取第三个...
Third element of a vector is :40 Fourth element of a vector is :50 访问向量元素的第二种方法是使用get(index)方法, 将向量的索引作为参数传递, 并返回Option <&t>类型的值。 让我们通过一个例子来理解: fn value(n:Option<&i32>) { match n ...
Added a hashmaps3 exercise for some advanced usage of hashmaps. Moved the original quiz2 to be strings4, since it only tested strings anyways. Reworked quiz2 into a new exercise that tests more chapters. Renamed option to options. options1: Rewrote parts of the exercise to remove the weir...
3.1 rust vector vec创建 use std::option::Option::*; fn main() { println!("---"); test_vec1(); test_vec2(); } fn test_vec1(){//let v: Vec<i32> = Vec::new();let mut v1 = Vec::new(); v1.push(1); v1.push(2); v1.push(3); println!("{:?