Microsoft.ML.Tokenizers contains the implmentation of the tokenization used in the NLP transforms.
$ dotnet add package Microsoft.ML.TokenizersMicrosoft.ML.Tokenizers provides an abstraction for tokenizers as well as implementations of common tokenization algorithms.
using Microsoft.ML.Tokenizers;
using System.IO;
using System.Net.Http;
//
// Using Tiktoken Tokenizer
//
// Initialize the tokenizer for the `gpt-4o` model. This instance should be cached for all subsequent use.
Tokenizer tokenizer = TiktokenTokenizer.CreateForModel("gpt-4o");
string source = "Text tokenization is the process of splitting a string into a list of tokens.";
Console.WriteLine($"Tokens: {tokenizer.CountTokens(source)}");
// prints: Tokens: 16
var trimIndex = tokenizer.GetIndexByTokenCountFromEnd(source, 5, out string processedText, out _);
Console.WriteLine($"5 tokens from end: {processedText.Substring(trimIndex)}");
// prints: 5 tokens from end: a list of tokens.
trimIndex = tokenizer.GetIndexByTokenCount(source, 5, out processedText, out _);
Console.WriteLine($"5 tokens from start: {processedText.Substring(0, trimIndex)}");
// prints: 5 tokens from start: Text tokenization is the
IReadOnlyList<int> ids = tokenizer.EncodeToIds(source);
Console.WriteLine(string.Join(", ", ids));
// prints: 1199, 4037, 2065, 374, 279, 1920, 315, 45473, 264, 925, 1139, 264, 1160, 315, 11460, 13
//
// Using Llama Tokenizer
//
// Open a stream to the remote Llama tokenizer model data file.
using HttpClient httpClient = new();
const string modelUrl = @"https://huggingface.co/hf-internal-testing/llama-tokenizer/resolve/main/tokenizer.model";
using Stream remoteStream = await httpClient.GetStreamAsync(modelUrl);
// Create the Llama tokenizer using the remote stream. This should be cached for all subsequent use.
Tokenizer llamaTokenizer = LlamaTokenizer.Create(remoteStream);
string input = "Hello, world!";
ids = llamaTokenizer.EncodeToIds(input);
Console.WriteLine(string.Join(", ", ids));
// prints: 1, 15043, 29892, 3186, 29991
Console.WriteLine($"Tokens: {llamaTokenizer.CountTokens(input)}");
// prints: Tokens: 5
The main types provided by this library are:
Microsoft.ML.Tokenizers.TokenizerMicrosoft.ML.Tokenizers.BpeTokenizerMicrosoft.ML.Tokenizers.EnglishRobertaTokenizerMicrosoft.ML.Tokenizers.TiktokenTokenizerMicrosoft.ML.Tokenizers.NormalizerMicrosoft.ML.Tokenizers.PreTokenizerMicrosoft.ML.Tokenizers is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.