FuzzySearch.FuzzyMatch

Parameters

Returns

bool Returns true if a match was found.

Description

Performs a fuzzy search for a pattern on a string.

using System;
using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEditor.Search;
using UnityEngine;

static class Example_FuzzySearch_FuzzyMatch
{
    [MenuItem("Examples/FuzzySearch/FuzzyMatch")]
    public static void Run()
    {
        const string pattern = "exfsfm";
        const string toBeSearched = nameof(Example_FuzzySearch_FuzzyMatch);

        long score = 0;
        if (FuzzySearch.FuzzyMatch(pattern, toBeSearched, ref score))
            Debug.Assert(score == 309);

        // This allocated list can be reused for multiple calls to FuzzyMatch
        var matches = new List<int>();
        if (FuzzySearch.FuzzyMatch(pattern, toBeSearched, ref score, matches))
        {
            var formattedMatch = RichTextFormatter.FormatSuggestionTitle(toBeSearched, matches);
            Debug.Log($"Found fuzzy pattern <i>{pattern}</i> in {formattedMatch} with indices " +
                $"{string.Join(",", matches.Select(m => m.ToString()))} and got a score of <b>{score}</b>");
        }
    }

    static class RichTextFormatter
    {
        static readonly char[] cache_result = new char[1024];
        public static string HighlightColorTag = EditorGUIUtility.isProSkin ? "<color=#FF6100>" : "<color=#EE4400>";
        public static string HighlightColorTagSpecial = EditorGUIUtility.isProSkin ? "<color=#FF6100>" : "<color=#BB1100>";

        public static string FormatSuggestionTitle(string title, List<int> matches)
        {
            return FormatSuggestionTitle(title, matches, HighlightColorTag, HighlightColorTagSpecial);
        }

        public static string FormatSuggestionTitle(string title, List<int> matches, string selectedTextColorTag, string specialTextColorTag)
        {
            const string closingTag = "</color>";
            int openCharCount = specialTextColorTag.Length;
            int closingCharCount = closingTag.Length;

            var N = title.Length + matches.Count * (closingCharCount + openCharCount);
            var MN = matches.Count;

            var result = cache_result;
            if (N > cache_result.Length)
                result = new char[N];

            int t_i = 0;
            int t_j = 0;
            int t_k = 0;
            string tag = null;
            var needToClose = false;

            for (int guard = 0; guard < N; ++guard)
            {
                if (tag == null && needToClose == false && t_k < MN)
                {
                    var indx = matches[t_k];
                    if (indx == t_i || indx == -t_i)
                    {
                        tag = (indx < 0) ? specialTextColorTag : selectedTextColorTag;
                        ++t_k;
                    }
                }

                if (tag != null)
                {
                    result[guard] = tag[t_j++];

                    if (t_j >= tag.Length)
                    {
                        if (tag != closingTag)
                            needToClose = true;

                        tag = null;
                        t_j = 0;
                    }
                }
                else
                {
                    result[guard] = title[Math.Min(t_i++, title.Length - 1)];

                    if (needToClose)
                    {
                        tag = closingTag;
                        needToClose = false;
                    }
                }
            }

            return new string(result, 0, N);
        }
    }
}

This can also be used easily in the context of a QueryEngine to enable fuzzy search.

using System.Collections.Generic;
using System.Linq;
using UnityEditor;
using UnityEditor.Search;
using UnityEngine;

static class Example_QueryEngine_FuzzyMatch
{
    static QueryEngine<MyObjectType> SetupQueryEngine()
    {
        var queryEngine = new QueryEngine<MyObjectType>();
        queryEngine.AddFilter("id", myObj => myObj.id);
        queryEngine.AddFilter("n", myObj => myObj.name);
        queryEngine.SetSearchDataCallback(myObj => new[] { myObj.id.ToString(), myObj.name });

        // Add a new operator token for fuzzy matching
        const string op = "~=";
        queryEngine.AddOperator(op);

        // Define what this operator does, and which types it operates on.
        queryEngine.AddOperatorHandler(op, (string ev, string fv) => FuzzySearch.FuzzyMatch(fv, ev));

        // Set the word matcher function to also support fuzzy matching
        queryEngine.SetSearchWordMatcher((word, exactMatch, stringComparison, searchDataCallbackValue) =>
        {
            if (exactMatch)
                return string.Equals(word, searchDataCallbackValue, stringComparison);
            return FuzzySearch.FuzzyMatch(word, searchDataCallbackValue);
        });

        return queryEngine;
    }

    static string[] s_Words = new[] { "bob", "cat", "car", "happy", "sad", "squirrel", "pizza", "dog", "over", "bing", "bong" };
    static IEnumerable<MyObjectType> GenerateData(int count)
    {
        for (var i = 0; i < count; ++i)
        {
            var wordCount = Random.Range(1, 6);
            var words = new List<string>();
            for (var j = 0; j < wordCount; ++j)
                words.Add(s_Words[Random.Range(0, s_Words.Length)]);

            var name = string.Join(" ", words);
            var id = $"{Random.Range(0, 1000)}-{s_Words[Random.Range(0, s_Words.Length)]}";
            yield return new MyObjectType() { id = id, name = name };
        }
    }

    static void FilterData(string text, QueryEngine<MyObjectType> queryEngine, IEnumerable<MyObjectType> data)
    {
        var query = queryEngine.ParseQuery(text);
        if (!query.valid)
        {
            foreach (var queryError in query.errors)
                Debug.LogFormat(LogType.Error, LogOption.NoStacktrace, null, $"Error parsing query at position {queryError.index}: {queryError.reason}");

            return;
        }

        var filteredData = query.Apply(data).ToList();
        Debug.LogFormat(LogType.Log, LogOption.NoStacktrace, null, $"Query \"{text}\" yielded {filteredData.Count} result{(filteredData.Count > 1 ? "s" : "")}");
        foreach (var filteredObject in filteredData)
            Debug.LogFormat(LogType.Log, LogOption.NoStacktrace, null, filteredObject.ToString());
    }

    [MenuItem("Examples/QueryEngine/FuzzyMatch")]
    public static void RunExample()
    {
        // Set up the query engine
        var queryEngine = SetupQueryEngine();

        var data = GenerateData(100);

        // Find all items with a name that match "ccs" (for example, "cat car squirrel" or "car cat sad")
        FilterData("n~=ccs", queryEngine, data);

        // Find all items with a name or an id that match "bob" (for example, "bob", "42-bob" or "bing over bong")
        FilterData("bob", queryEngine, data);
    }

    class MyObjectType
    {
        public string id { get; set; }
        public string name { get; set; } = string.Empty;

        public override string ToString()
        {
            return $"({id}, {name})";
        }
    }
}