strcompare

strcompare is a zig library implementing 3 of the most common string comparison algorithms:

• Hamming distance
• Levenshtein distance
• Damerau-Levenshtein distance (specifically, the optimal string alignment distance)

Usage

The library provides two convenience functions: similarity and distance.

Both functions accept a Metrics argument, one of:

pub const Metrics = enum { 
    Damerau,
    Hamming,
    Levenshtein,
};

distance

distance will return the edit distance, a u64.

It accepts the following arguments:

• alloc: an std.mem.Allocator
• metric: one of the Metrics
• a, b: strings to compare

Example:

const a = "kitten";
const b = "sitting";

const d = distance(alloc, Metrics.Levenshtein, a, b);

std.debug.print("distance: {d}\n", .{d}); 
// 
// distance: 3
//

similarity

similarity returns a weighted distance, that is, an f64 from 0.0 to 1.0. It will return 0.0 if the strings differ completely and 1.0 if they are identical.

It accepts the following arguments:

• alloc: an std.mem.Allocator
• metric: one of the Metrics
• a, b: strings to compare

Example:

const a = "kitten";
const b = "sitting";

const d = similarity(alloc, Metrics.Levenshtein, a, b);

std.debug.print("similarity: {d:.0}%\n", .{d*100.0}); 
// 
// similarity: 57%
//

Installing

After acquiring the repo's code, run:

zig fetch --save ./path/to/strcompare 

then add the following to your build.zig

    const pkg = b.dependency("strcompare", .{});
    exe.root_module.addImport("strcompare", pkg.module("strcompare"));

Do the same for your tests:

    const exe_unit_tests = b.addTest(.{
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });

    exe_unit_tests.root_module.addImport("strcompare", pkg.module("strcompare"));

You should now be able to import the module with:

const strcompare = @import("strcompare");
const Metrics = strcompare.Metrics;
const distance = strcompare.distance;
const similarity = strcompare.similarity;

fn dist() !void {
    const a = "a";
    const b = "bb";
    const alloc = std.heap.page_allocator;

    const d = try distance(alloc, Metrics.Levenshtein, a, b);
    std.debug.print("distance: {d}\n", .{d});
}