map是迭代器的一个方法,我们之前用过,它接收一个闭包,闭包的参数是迭代的项,然后要求闭包返回值。 其实我们也可以直接传一个函数。 fn main() { let list_of_numbers = vec![1, 2, 3]; let list_of_strings: Vec<String> = list_of_numbers.iter().map(ToString::to_string).collect(); } ...
" ", "world"] -> "Hello World"pubfncapitalize_words_string(words:&[&str])->String{words.iter().map(|x|capitalize_first(x)).collect::<String>()}#[cfg(test)]modtests{usesuper::*;#[test]fntest_success(){assert_eq!(capitalize_first(...
impl InvertedIndex { fn query(&self, term: &str) -> Vec<String> { let term_lowercase = term.to_lowercase(); if let Some(doc_ids) = self.indexes.get(&term_lowercase) { doc_ids .iter() .filter_map(|doc_id| { self.documents .get(doc_id) .map(|doc| highlight(&term_lowercase,...
For containers, we typically obtain the corresponding iterators using theiter,iter_mut, orinto_itermethods, but there are often additional options. For instance,std::collections::HashMapoffers a wide choice of iterators: iter, to visit all the key-value pairs (with both the key and the value...
iter::repeat_with(|| { // Try stealing a batch of tasks from the global queue. global .steal() //.steal_batch_and_pop(local) // Or try stealing a task from one of the other threads. .or_else(|| stealers.iter().map(|s| s.steal()).collect()) ...
map.insert("size", "10 m^2"); for p in map.iter() { println!("{:?}", p); } } 运行结果: ("color", "red") ("size", "10 m^2") 迭代元素是表示键值对的元组。 Rust 的映射表是十分方便的数据结构,当使用 insert 方法添加新的键值对的时候,如果已经存在相同的键,会直接覆盖对应的值...
[1, 2, 3]; let v1_iter = v1.iter(); let total: i32 = v1_iter.sum(); // sum消费了迭代器 assert_eq!(total, 6); }// 消费器适配器(产生迭代器的方法)// map(),filter(),zip(),let v1: Vec<i32> = vec![1, 2, 3];let v2: Vec<_> = v1.iter().map(|x| x + 1)...
iter().map(|x| x * 2).collect::<Vec<i32>>(); println!("{:?}", nums); //output: [2, 4, 6, 8, 10]A slight digression. What if we wanted to use mutable iterator to add elements to the vector like so: let mut nums = vec![1, 2, 3, 4, 5]; for i in &mut nums ...
;posts.truncate(limit);letpost_idx_to_ids:Vec<(usize,i64)>=posts.iter().enumerate().map(|(idx,post)|(idx,post.id)).collect();// fetch post comments one after another.for(index,post_id)inpost_idx_to_ids{letcomments=fetch_comments(&client,post_id).await?;posts[index].comments=...
do_stuff() // error // par_iter() cant work on string because // it doesnt know where to cut the byte boundaries let v = s.iter().collect::<Vec<char>>9); // so convert to vector of char each 4 bytes v.par_iter().map(|ch| ch.to_ascii_lowercase()).do_stuff() // now...