Levenshtein Transformations

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Transform an array into any other array of the same type, or a string into any other string, using only the three transformations replace, delete and insert.

Installation

Open your Swift package in GNOME Builder, Xcode, or any other IDE.
Open the Package.swift file.
Into the Package initializer, under dependencies, paste:

.package(url: "https://github.com/david-swift/LevenshteinTransformations", from: "0.1.0")

Usage

let source = [1, 2, 5, 6]
let target = [0, 1, 5, 6, 10]

There are three functions available for arrays containing elements conforming to Equatable and strings.

Arrays with `Equatable` Elements and Strings

Levenshtein Distance

Get the Levenshtein distance with levenshteinDistance(to:):

print(source.levenshteinDistance(to: target))

This example outputs 3.

Transformation Steps

Get the individual transformation steps with getTransformations(to:).

print(source.getTransformations(to: target).map { $0.description(source: source) }.joined(separator: "\n"))

This example prints the descriptions of the transformations:

Replace '1' at position 0 with '0'
Replace '2' at position 1 with '1'
Insert '10' at position 4

Run Functions for the Steps

Directly run functions for the replace, delete and insert transformations using the transform(to:functions:) function.

var modified = source

source.transform(
    to: target,
    functions: .init { index, element in
        modified[index] = element
    } delete: { index in
        modified.remove(at: index)
    } insert: { index, element in
        modified.insert(element, at: index)
    }
)

print(modified == target)

This example outputs true.

Arrays with `Identifiable` Elements

The same functions are available for arrays with identifiable elements, but they are named differently to avoid conflicts:

identifiableLevenshteinDistance(to:)
identifiableGetTransformations(to:)
identifiableTransform(to:functions:)

Thanks

The contributors
SwiftLint for checking whether code style conventions are violated
The programming language Swift
SourceDocs used for generating the docs

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