Struct eddie::str::Levenshtein

pub struct Levenshtein { /* fields omitted */ }

Levenshtein distance.

See the detailed description.

Usage

use eddie::Levenshtein;

let lev = Levenshtein::new();
let dist = lev.distance("martha", "marhta");
assert_eq!(dist, 2);

Complementary metrics

Relative distance:

let dist = lev.distance(s1, s2);
let rel = lev.rel_dist(s1, s2);
let max_len = max(s1.len(), s2.len());
assert_eq!(rel, dist as f64 / max_len as f64);

Similarity:

let rel = lev.rel_dist(s1, s2);
let sim = lev.similarity(s1, s2);
assert_eq!(sim, 1.0 - rel);

Methods

impl Levenshtein

pub fn new() -> Self

Creates a new instance of Levenshtein struct with an internal state for the metric methods to reuse.

Example

use eddie::Levenshtein;

let lev: Levenshtein = Levenshtein::new();

pub fn distance(&self, str1: &str, str2: &str) -> usize

Distance metric. Returns a number of edits (character additions, deletions, and substitutions) required to transform one string into the other.

Example

let dist = lev.distance("martha", "marhta");
assert_eq!(dist, 2);

pub fn rel_dist(&self, str1: &str, str2: &str) -> f64

Relative distance metric. Returns a number of edits relative to the length of the longest string, ranging from 0.0 (equality) to 1.0 (nothing in common).

Example

let dist = lev.rel_dist("martha", "marhta");
assert!((dist - 0.333).abs() < 0.001);

pub fn similarity(&self, str1: &str, str2: &str) -> f64

Similarity metric. Inversion of relative distance, ranging from 1.0 (equality) to 0.0 (nothing in common).

Example

let sim = lev.similarity("martha", "marhta");
assert!((sim - 0.666).abs() < 0.001);