Flint 0.2.0

Flint is a lightweight, zero-dependency C# library that provides fast text matching utilities using the Aho-Corasick algorithm.

Usage Examples

Basic

using Flint;

var matcher = new TextMatcher(new[] { "cat", "dog" });
var results = matcher.Find("The dog chased the cat.");

foreach (var match in results)
{
    Console.WriteLine($"Found '{match.Value}' at index {match.StartIndex}.");
}

Output:

Found 'dog' at index 4.
Found 'cat' at index 19.

An optional StringComparison can be passed to TextMarcher, influencing it's behavior when performing searches/replacement. If none is given, it will default to StringComparison.CurrentCulture.

using Flint;

var matcher = new TextMatcher(new[] { "cat", "dog" }, StringComparison.OrdinalIgnoreCase);
var results = matcher.Find("The DOG chased the CaT.");

foreach (var match in results)
{
    Console.WriteLine($"Found '{match.Value}' at index {match.StartIndex}.");
}

Output:

Found 'DOG' at index 4.
Found 'CaT' at index 19.

Scan multiple texts with FindAll

using Flint;

var patterns = new[] { "cat", "dog", "bird" };
var matcher = new TextMatcher(patterns);

var texts = new[]
{
    "The dog chased the cat.",
    "A bird watched them from above.",
    "No animals here."
};

var all = matcher.FindAll(texts);

foreach (var kv in all)
{
    Console.WriteLine(kv.Key);
    foreach (var m in kv.Value)
    {
        Console.WriteLine($"Found '{m.Value}' at index {m.StartIndex}.");
    }
}

Example output:

The dog chased the cat.
Found 'cat' at index 19.
Found 'dog' at index 4.
A bird watched them from above.
Found 'bird' at index 2.
No animals here.

Overlapping and nested matches

using Flint;

var matcher = new TextMatcher(new[] { "he", "she", "his", "hers" });
var results = matcher.Find("she is his hero");

foreach (var m in results)
{
    Console.WriteLine($"Found '{m.Value}' at index {m.StartIndex}.");
}

Example output:

Found 'she' at index 0.
Found 'he' at index 1.
Found 'his' at index 7.
Found 'he' at index 10.

Replace all matches with a single value

using Flint;

var matcher = new TextMatcher(new[] { "cat", "dog" });
var replaced = matcher.Replace("The dog chased the cat.", "animal");
Console.WriteLine(replaced);

Output:

The animal chased the animal.

Replace matches using a function

using Flint;

var matcher = new TextMatcher(new[] { "cat", "dog" });
var replaced = matcher.Replace(
    "The dog chased the cat.",
    match => match.Value.ToUpper()
);
Console.WriteLine(replaced);

Output:

The DOG chased the CAT.

Replace each pattern with a different value

using Flint;

var matcher = new TextMatcher(new[] { "cat", "dog" });
var replaced = matcher.Replace(
    "The dog chased the cat.",
    new[] { "feline", "canine" }
);
Console.WriteLine(replaced);

Output:

The canine chased the feline.

Load patterns from a file

using Flint;

var patterns = File.ReadAllLines("patterns.txt")
                   .Where(l => !string.IsNullOrWhiteSpace(l));

var matcher = new TextMatcher(patterns);

var text = File.ReadAllText("large_input.txt");
var hits = matcher.Find(text).ToArray();

Console.WriteLine($"Found {hits.Length} matches.");

Support

• .NET Standard 2.0 and .NET 8.0

License

Flint is licensed under the MIT License.