Grapheme Cluster and Word boundaries according to UAX#29 rules
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Latest commit 703e9c2 Apr 30, 2018

Iterators which split strings on Grapheme Cluster or Word boundaries, according to the Unicode Standard Annex #29 rules.

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extern crate unicode_segmentation;

use unicode_segmentation::UnicodeSegmentation;

fn main() {
    let s = "a̐éö̲\r\n";
    let g = UnicodeSegmentation::graphemes(s, true).collect::<Vec<&str>>();
    let b: &[_] = &["a̐", "é", "ö̲", "\r\n"];
    assert_eq!(g, b);

    let s = "The quick (\"brown\") fox can't jump 32.3 feet, right?";
    let w = s.unicode_words().collect::<Vec<&str>>();
    let b: &[_] = &["The", "quick", "brown", "fox", "can't", "jump", "32.3", "feet", "right"];
    assert_eq!(w, b);

    let s = "The quick (\"brown\")  fox";
    let w = s.split_word_bounds().collect::<Vec<&str>>();
    let b: &[_] = &["The", " ", "quick", " ", "(", "\"", "brown", "\"", ")", " ", " ", "fox"];
    assert_eq!(w, b);


unicode-segmentation does not depend on libstd, so it can be used in crates with the #![no_std] attribute.

You can use this package in your project by adding the following to your Cargo.toml:

unicode-segmentation = "1.1.0"

Change Log


  • New GraphemeCursor API allows random access and bidirectional iteration.
  • Fixed incorrect splitting of certain emoji modifier sequences.


  • Add as_str methods to the iterator types.


  • Code cleanup and additional tests.


  • Fix a bug affecting some grapheme clusters containing Prepend characters.


  • Upgrade to Unicode 9.0.0.