Text jaro distance

Development build. This page describes main, not a released package. The latest published Lodestar.Text is 0.4.0 — read its documentation.

Jaro.Distance

1 - Similarity, for code that wants a distance rather than a score.

public static double Distance(ReadOnlySpan<char> a, ReadOnlySpan<char> b, TextElement element = TextElement.Utf16Unit)

Parameters — a and b are the two strings to compare; element says what counts as one character, exactly as it does for Similarity, which this subtracts from 1.

Returns — double in [0, 1], larger meaning less alike. 0 for equal non-empty inputs — see the trap below for what two empty ones give.

Example — two names that a human would call a near-match.

using Lodestar.Text.Distances;

double d = Jaro.Distance("DWAYNE", "DUANE");   // => 0.1777…

Remarks — this exists so that Jaro can be plugged into code written against a distance rather than a similarity: a clustering routine, a sort where smaller is better, a threshold expressed as "at most". It carries no information Similarity does not.

The trap it inherits is the empty case running the wrong way: two empty strings are 0 similar and therefore 1 apart, the maximum distance this can return. If empty fields are common in your data, that is a pair of blanks landing at the far end of every ranking.

Applies to — net10.0, netstandard2.0.

See also — Jaro.Similarity, JaroWinkler.Distance, the Python equivalence table.