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14cf91e0ef
Using `x.len()` on a str returns the number of bytes, which is not
always the same as the number of characters. For example, the characters
'ö' or '香' are representing using more than one byte. This leads
to strange behaviour (e.g. `levenshtein("a", "ä")` would return 0).
Replace calls to `str.len()` with `str.chars().count()`, which returns
the correct number of characters in a string.
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| src | ||
| tests | ||
| .gitignore | ||
| .travis.yml | ||
| appveyor.yml | ||
| bootstrap.sh | ||
| Cargo.toml | ||
| LICENSE | ||
| README.md | ||
| Vagrantfile | ||
strsim-rs 
Rust implementations of string similarity metrics:
- Hamming
- Levenshtein and Damerau-Levenshtein
- Jaro and Jaro-Winkler - this implementation of Jaro-Winkler does not limit the common prefix length
Installation
# Cargo.toml
[dependencies]
strsim = "0.4.0"
Usage
extern crate strsim;
use strsim::{hamming, levenshtein, damerau_levenshtein, jaro, jaro_winkler,
levenshtein_against_vec, damerau_levenshtein_against_vec,
jaro_against_vec, jaro_winkler_against_vec};
fn main() {
match hamming("hamming", "hammers") {
Ok(distance) => assert_eq!(3, distance),
Err(why) => panic!("{:?}", why)
}
assert_eq!(3, levenshtein("kitten", "sitting"));
assert_eq!(1, damerau_levenshtein("specter", "spectre"));
assert!((0.392 - jaro("Friedrich Nietzsche", "Jean-Paul Sartre")).abs() <
0.001);
assert!((0.911 - jaro_winkler("cheeseburger", "cheese fries")).abs() <
0.001);
// get vectors of values back
let v = vec!["test", "test1", "test12", "test123", "", "tset"];
assert_eq!(levenshtein_against_vec("test", &v),
vec![0, 1, 2, 3, 4, 2]);
assert_eq!(damerau_levenshtein_against_vec("test", &v),
vec![0, 1, 2, 3, 4, 1]);
let jaro_distances = jaro_against_vec("test", &v);
let jaro_expected = vec![1.0, 0.933333, 0.888889, 0.857143, 0.0, 0.916667];
let jaro_delta: f64 = jaro_distances.iter()
.zip(jaro_expected.iter())
.map(|(x, y)| (x - y).abs() as f64)
.fold(0.0, |x, y| x + y as f64);
assert!(jaro_delta < 0.0001);
let jaro_winkler_distances = jaro_winkler_against_vec("test", &v);
let jaro_winkler_expected = vec![1.0, 0.96, 0.933333, 0.914286, 0.0, 0.925];
let jaro_winkler_delta = jaro_winkler_distances.iter()
.zip(jaro_winkler_expected.iter())
.map(|(x, y)| (x - y).abs() as f64)
.fold(0.0, |x, y| x + y as f64);
assert!(jaro_winkler_delta < 0.0001);
}
Development
Install Vagrant, and run vagrant up.
License
MIT