How can I sort the characters of a string in Rust?

Question

I have the string "laxmi" and I need to sort it in descending alphabetical order, producing "xmlia". I have written this:

fn main() {
    let wordy: String = "I am a hello world example";

    let chars: Vec<char> = wordy.chars().vector();
    chars.sort_by(|a, b| b.cmp(a));

    // let s: String = chars.into_iter().collect();
    println!("test{:?}", chars);
    let s = String::from_iter(chars);
    println!("{}", s);
}

This only works if wordy is a &str, but I have a String. How can I convert the String to a vector of char so that I can sort the string?

Solution 1

I did this and got the desired output. However this may not be the best way.

use std::iter::Iterator;
use std::iter::FromIterator;

fn main() {
    let wordy: String = "I am a hello world example".to_owned();
    let s_slice: &str = &wordy[..];

    let mut chars: Vec<char> = s_slice.chars().collect();
    chars.sort_by(|a, b| b.cmp(a));

    println!("test{:?}", chars);
    let s = String::from_iter(chars);
    println!("{}", s);
}

Solution 2

If you're okay with using crates, you can use the itertools crate to simplify things quite a bit.

Add the crate to your Cargo.toml:

[dependencies]
itertools = "0.9.0"

Then use it in your file to sort and reverse the string.

use itertools::Itertools;

fn main() {
    let wordy = "I am a hello world example";

    let s = wordy.chars().sorted().rev().collect::<String>();

    println!("{}", s);
}