RustDay05------Exercise[41-50]
41.使用模块的函数
mod是用于创建模块的关键字。模块是一种组织代码的方式，它可以包含函数 (fn)、结构体 (struct)、枚举 (enum)、常量 (const)、其他模块 (mod) 等。- 模块用于组织和封装代码，帮助将代码分割成可管理的单元。模块可以形成层次结构，允许你更好地组织和管理代码。
模块的函数一般是私有的,需要使用pub关键词将其暴露
// modules1.rs
// Execute `rustlings hint modules1` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
mod sausage_factory {
// Don't let anybody outside of this module see this!
fn get_secret_recipe() -> String {
String::from("Ginger")
}
pub fn make_sausage() {
get_secret_recipe();
println!("sausage!");
}
}
fn main() {
sausage_factory::make_sausage();
}
42.暴露读取私有方法的函数的属性的模板变量,以选择性地公布部分属性(设置为pub)
// modules2.rs
// You can bring module paths into scopes and provide new names for them with the
// 'use' and 'as' keywords. Fix these 'use' statements to make the code compile.
// Execute `rustlings hint modules2` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
mod delicious_snacks {
// TODO: Fix these use statements
pub use self::fruits::PEAR as fruit;
pub use self::veggies::CUCUMBER as veggie;
mod fruits {
pub const PEAR: &'static str = "Pear";
pub const APPLE: &'static str = "Apple";
}
mod veggies {
pub const CUCUMBER: &'static str = "Cucumber";
pub const CARROT: &'static str = "Carrot";
}
}
fn main() {
println!(
"favorite snacks: {} and {}",
delicious_snacks::fruit,
delicious_snacks::veggie
);
}
43.导入默认库的宏和库函数
// modules3.rs
// You can use the 'use' keyword to bring module paths from modules from anywhere
// and especially from the Rust standard library into your scope.
// Bring SystemTime and UNIX_EPOCH
// from the std::time module. Bonus style points if you can do it with one line!
// Execute `rustlings hint modules3` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
// TODO: Complete this use statement
use std::time::SystemTime;
use std::time::UNIX_EPOCH;
fn main() {
match SystemTime::now().duration_since(UNIX_EPOCH) {
Ok(n) => println!("1970-01-01 00:00:00 UTC was {} seconds ago!", n.as_secs()),
Err(_) => panic!("SystemTime before UNIX EPOCH!"),
}
}
44.new一个hashMap
HashMap::new()注意末尾条件,添加足够种类和数量水果即可
// hashmaps1.rs
// A basket of fruits in the form of a hash map needs to be defined.
// The key represents the name of the fruit and the value represents
// how many of that particular fruit is in the basket. You have to put
// at least three different types of fruits (e.g apple, banana, mango)
// in the basket and the total count of all the fruits should be at
// least five.
//
// Make me compile and pass the tests!
//
// Execute `rustlings hint hashmaps1` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
use std::collections::HashMap;
fn fruit_basket() -> HashMap {
let mut basket = HashMap::new();// TODO: declare your hash map here.
// Two bananas are already given for you :)
basket.insert(String::from("banana"), 2);
// TODO: Put more fruits in your basket here.
basket.insert("666".to_string(),3);
basket.insert("999".to_string(),1);
basket
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn at_least_three_types_of_fruits() {
let basket = fruit_basket();
assert!(basket.len() >= 3);
}
#[test]
fn at_least_five_fruits() {
let basket = fruit_basket();
assert!(basket.values().sum::() >= 5);
}
}
45.hashmap的基础插入操作
注意末尾测试的要求即可
// hashmaps2.rs
// A basket of fruits in the form of a hash map is given. The key
// represents the name of the fruit and the value represents how many
// of that particular fruit is in the basket. You have to put *MORE
// THAN 11* fruits in the basket. Three types of fruits - Apple (4),
// Mango (2) and Lychee (5) are already given in the basket. You are
// not allowed to insert any more of these fruits!
//
// Make me pass the tests!
//
// Execute `rustlings hint hashmaps2` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
use std::collections::HashMap;
#[derive(Hash, PartialEq, Eq)]
enum Fruit {
Apple,
Banana,
Mango,
Lychee,
Pineapple,
}
fn fruit_basket(basket: &mut HashMap) {
let fruit_kinds = vec![
Fruit::Apple,
Fruit::Banana,
Fruit::Mango,
Fruit::Lychee,
Fruit::Pineapple,
];
for fruit in fruit_kinds {
// TODO: Put new fruits if not already present. Note that you
// are not allowed to put any type of fruit that's already
// present!
}
}
#[cfg(test)]
mod tests {
use super::*;
fn get_fruit_basket() -> HashMap {
let mut basket = HashMap::::new();
basket.insert(Fruit::Apple, 4);
basket.insert(Fruit::Mango, 2);
basket.insert(Fruit::Lychee, 5);
// at_least_five_types_of_fruits 种类>=5
// greater_than_eleven_fruits 总数 >=1
basket.insert(Fruit::Banana, 5);
basket.insert(Fruit::Pineapple, 5);
basket
}
#[test]
fn test_given_fruits_are_not_modified() {
let mut basket = get_fruit_basket();
fruit_basket(&mut basket);
assert_eq!(*basket.get(&Fruit::Apple).unwrap(), 4);
assert_eq!(*basket.get(&Fruit::Mango).unwrap(), 2);
assert_eq!(*basket.get(&Fruit::Lychee).unwrap(), 5);
}
#[test]
fn at_least_five_types_of_fruits() {
let mut basket = get_fruit_basket();
fruit_basket(&mut basket);
let count_fruit_kinds = basket.len();
assert!(count_fruit_kinds >= 5);
}
#[test]
fn greater_than_eleven_fruits() {
let mut basket = get_fruit_basket();
fruit_basket(&mut basket);
let count = basket.values().sum::();
assert!(count > 11);
}
}
46.查看hashmap是否包含某个键
这一题有点综合性难度了,我们需要对每场比赛的双方统计得球和失球的次数,然后通过hashMap传递出去
// hashmaps3.rs
// A list of scores (one per line) of a soccer match is given. Each line
// is of the form :
// ,,,
// Example: England,France,4,2 (England scored 4 goals, France 2).
// You have to build a scores table containing the name of the team, goals
// the team scored, and goals the team conceded. One approach to build
// the scores table is to use a Hashmap. The solution is partially
// written to use a Hashmap, complete it to pass the test.
// Make me pass the tests!
// Execute `rustlings hint hashmaps3` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
use std::collections::HashMap;
// A structure to store team name and its goal details.
struct Team {
name: String,
goals_scored: u8,
goals_conceded: u8,
}
fn build_scores_table(results: String) -> HashMap {
// The name of the team is the key and its associated struct is the value.
let mut scores: HashMap = HashMap::new();
for r in results.lines() {
let v: Vec<&str> = r.split(',').collect();
let team_1_name = v[0].to_string();
let team_1_score: u8 = v[2].parse().unwrap();
let team_2_name = v[1].to_string();
let team_2_score: u8 = v[3].parse().unwrap();
// TODO: Populate the scores table with details extracted from the
// current line. Keep in mind that goals scored by team_1
// will be number of goals conceded from team_2, and similarly
// goals scored by team_2 will be the number of goals conceded by
// team_1.
if !scores.contains_key(&team_1_name) {
// 创建新用户 都初始化为0
scores.insert(team_1_name.clone(),Team{
name: team_1_name.clone(),
goals_scored: 0,
goals_conceded: 0,
});
};
if !scores.contains_key(&team_2_name) {
// 创建新用户 都初始化为0
scores.insert(team_2_name.clone(),Team{
name: team_2_name.clone(),
goals_scored: 0,
goals_conceded: 0,
});
};
let team1=scores.get_mut(&team_1_name).unwrap();
team1.goals_scored+=team_1_score;
team1.goals_conceded+=team_2_score;
let team2=scores.get_mut(&team_2_name).unwrap();
team2.goals_scored+=team_2_score;
team2.goals_conceded+=team_1_score;
}
scores
}
#[cfg(test)]
mod tests {
use super::*;
fn get_results() -> String {
let results = "".to_string()
+ "England,France,4,2\n"
+ "France,Italy,3,1\n"
+ "Poland,Spain,2,0\n"
+ "Germany,England,2,1\n";
results
}
#[test]
fn build_scores() {
let scores = build_scores_table(get_results());
let mut keys: Vec<&String> = scores.keys().collect();
keys.sort();
assert_eq!(
keys,
vec!["England", "France", "Germany", "Italy", "Poland", "Spain"]
);
}
#[test]
fn validate_team_score_1() {
let scores = build_scores_table(get_results());
let team = scores.get("England").unwrap();
assert_eq!(team.goals_scored, 5);
assert_eq!(team.goals_conceded, 4);
}
#[test]
fn validate_team_score_2() {
let scores = build_scores_table(get_results());
let team = scores.get("Spain").unwrap();
assert_eq!(team.goals_scored, 0);
assert_eq!(team.goals_conceded, 2);
}
}