How to write a function that returns Vec?

Question

I\'m reading the documentation and trying to write some basic file I/O code as a vehicle to help me learn Rust.

The following doesn\'t compile:

use s         


        

Answer 1

You don't. Path is a type that has no size, and is only usable through indirection (such as &Path or Box<Path>). In this sense, it is like the type str or [u8] — neither can be directly used, only indirectly.

What you probably want is a PathBuf, which represents an owned path. It is the equivalent of String for &str and Vec<u8> for &[u8].

After changing the return type, you have to properly map the results of the iterator to create your desired type:

use std::{fs,
          io,
          path::{Path, PathBuf}};

pub fn read_filenames_from_dir<P>(path: P) -> Result<Vec<PathBuf>, io::Error>
where
    P: AsRef<Path>,
{
    fs::read_dir(path)?
        .into_iter()
        .map(|x| x.map(|entry| entry.path()))
        .collect()
}

fn main() {
    println!("{:?}", read_filenames_from_dir("/etc"));
}