How to Use ICU Collation in Rust

Use the icu_collator crate to sort strings according to Unicode Collation Algorithm rules. Add the dependency to your Cargo.toml and initialize a collator with your target locale.

[dependencies]
icu_collator = "1.5"
icu_locid = "1.5"

use icu_collator::Collator;
use icu_locid::Locale;

fn main() -> icu_collator::Result<()> {
    let locale: Locale = "en-US".parse()?;
    let mut collator = Collator::try_new(&locale)?;
    let mut items = vec!["apple", "Banana", "cherry"];
    collator.sort(&mut items);
    println!("{:?}", items);
    Ok(())
}

ICU Collation sorts text based on language rules rather than just raw character codes, ensuring words like 'apple' and 'Banana' sort correctly for humans. It matters when building search features or lists for international users so that sorting feels natural in their specific language. Think of it as a dictionary that knows how to order words for a specific country, rather than a simple alphabetical list.