Advertisements I’m new to this language and am currently reading Rust in action. I understand why you’re able to access the vector after a for loop. However, I don’t understand why this works: let list = [1, 2, 3, 4, 5]; for item in list { println!("{}", item); } println!("{:#?}", list); If I try the… Read More Why is an array not moved after the for block like a vector?

Advertisements Here’s an example of my code: use bytes::Bytes; use regex::bytes::Regex as BytesRegex; fn main() { let val = b"2020-01-01"; let my_regex = BytesRegex::new(r"\d{4}-(\d{2})-\d{2}").unwrap(); let month = my_regex.captures(val).unwrap().get(1).unwrap(); let month_digit = std::str::from_utf8(month.as_bytes()).unwrap().parse::<u8>().unwrap(); println!("month smaller than 12: {}", month_digit<=12); } https://gist.github.com/rust-play/92d4e4855015317451abad775adceec1 Like this, I was able to print out the captured group as an unsigned integer.… Read More How do I extract a number in decimal representation from a `&[u8]` and compare it with an integer?

Advertisements I have a closure which I cannot change, which I need to run in a new thread and to which I need to pass a variable. This is how I imagine the code to look like: use std::thread; fn main() { // I can not influence this closure, but this is what it looks… Read More How to pass arguments to a thread in rust?

Advertisements I have a Container struct containing a vector, which I’d like to consume while doing some work on it. For a standalone vector the following works: fn empty(vec : &mut Vec<f32>){ vec.into_iter().for_each(|x|println!("value: {:?}", x)); } fn main() { let mut vec = vec![1.0,2.0,3.0,4.0]; empty(&mut vec); assert!(0 == vec.len()); } However, trying this with the… Read More Rust consume a vector inside a struct

Advertisements This is just example code. fn main() { let mut vec = vec![4, 3, 6, 7, 5, 8, 1, 2, 9, 0, 1]; println!("{:?}", solution(&mut vec)); } fn solution(vec: &mut std::vec::Vec<i32>) -> (i32, i32, i32) { let mut copy = vec; copy.sort(); println!("{:?}",copy); let mut len: i32 = match copy.len().try_into() { Ok(v) => v,… Read More How can I pass a value to a function without moving ownership, just by passing the value in Rust?

Advertisements I currently have the following function: fn filter_files<P>(input_path: P) -> Result<Vec<DirEntry>, Box<dyn error::Error>> where P: AsRef<Path> { fs::read_dir(input_path)? .into_iter() .filter_map(|res| res.ok()) .filter(|dir_entry| dir_entry.file_name().to_str().unwrap().starts_with("_x")) .collect() } Where I am attempting to filter out files that start with _x. I would like to have this function return the filtered Vec<DirEntry> directly instead of having to make… Read More How to collect an iterator into a Result?

Advertisements I have a type defined as follows: pub struct State<T: Clone + Eq> { pub db: HashSet<T>, } And I have a function that looks like the following: fn check(&self) -> Result<(), Error> { self.db.iter().for_each(|elem| elem.check()); Ok(()) } So I want to call check function for each of the element in HashSet. I just… Read More How to apply function that returns Result to each element of HashSet in Rust?

Advertisements Is something like possible in rust? fn replace_abracadabra(s: &str) -> &str { if s.starts_with("abracadabra") { "i am static" + s.chars().last().unwrap() } else { s } } Here, "i am static" + s.chars().last().unwrap() is all borrowed, but is now a non-contiguous block of memory. >Solution : No, slices (both string and array slices) are contiguous… Read More `&str` as pointing to non-contiguous portion of memory

Advertisements I need to write a function that takes a string as an input, splits it by the line break character and trims all the redundant break characters in each entry of the split. I’ve come up with the following: fn split_and_trim(text: &String) { let lines – text.split(‘\n’).map(|l| String::from(l).trim()); println!("{:?}", lines) } But this code… Read More Map the split to trim each entry