TextCatalog.FeaturizeText 方法

定义

命名空间:

Microsoft.ML

程序集:

Microsoft.ML.Transforms.dll

包:

Microsoft.ML v2.0.0

重载

FeaturizeText(TransformsCatalog+TextTransforms, String, String)	创建一个 TextFeaturizingEstimator，它将文本列转换为特征化向量，该矢量 Single 表示 n 元语法和 char-gram 的规范化计数。
FeaturizeText(TransformsCatalog+TextTransforms, String, TextFeaturizingEstimator+Options, String[])	创建一个 TextFeaturizingEstimator，它将文本列转换为特征化向量 Single ，表示 n 元克和字符克的规范化计数。

FeaturizeText(TransformsCatalog+TextTransforms, String, String)

创建一个 TextFeaturizingEstimator，它将文本列转换为特征化向量，该矢量 Single 表示 n 元语法和 char-gram 的规范化计数。

public static Microsoft.ML.Transforms.Text.TextFeaturizingEstimator FeaturizeText (this Microsoft.ML.TransformsCatalog.TextTransforms catalog, string outputColumnName, string inputColumnName = default);

static member FeaturizeText : Microsoft.ML.TransformsCatalog.TextTransforms * string * string -> Microsoft.ML.Transforms.Text.TextFeaturizingEstimator

<Extension()>
Public Function FeaturizeText (catalog As TransformsCatalog.TextTransforms, outputColumnName As String, Optional inputColumnName As String = Nothing) As TextFeaturizingEstimator

参数

catalog

TransformsCatalog.TextTransforms

与文本相关的转换的目录。

outputColumnName

String

由转换 inputColumnName生成的列的名称。 此列的数据类型将是一 Single个向量。

inputColumnName

String

要转换的列的名称。 If set to null, the value of the outputColumnName will be used as source. 此估算器对文本数据进行操作。

返回

TextFeaturizingEstimator

示例

using System;
using System.Collections.Generic;
using Microsoft.ML;

namespace Samples.Dynamic
{
    public static class FeaturizeText
    {
        public static void Example()
        {
            // Create a new ML context, for ML.NET operations. It can be used for
            // exception tracking and logging, as well as the source of randomness.
            var mlContext = new MLContext();

            // Create a small dataset as an IEnumerable.
            var samples = new List<TextData>()
            {
                new TextData(){ Text = "ML.NET's FeaturizeText API uses a " +
                    "composition of several basic transforms to convert text " +
                    "into numeric features." },

                new TextData(){ Text = "This API can be used as a featurizer to " +
                    "perform text classification." },

                new TextData(){ Text = "There are a number of approaches to text " +
                    "classification." },

                new TextData(){ Text = "One of the simplest and most common " +
                    "approaches is called “Bag of Words”." },

                new TextData(){ Text = "Text classification can be used for a " +
                    "wide variety of tasks" },

                new TextData(){ Text = "such as sentiment analysis, topic " +
                    "detection, intent identification etc." },
            };

            // Convert training data to IDataView.
            var dataview = mlContext.Data.LoadFromEnumerable(samples);

            // A pipeline for converting text into numeric features.
            // The following call to 'FeaturizeText' instantiates 
            // 'TextFeaturizingEstimator' with default parameters.
            // The default settings for the TextFeaturizingEstimator are
            //      * StopWordsRemover: None
            //      * CaseMode: Lowercase
            //      * OutputTokensColumnName: None
            //      * KeepDiacritics: false, KeepPunctuations: true, KeepNumbers:
            //          true
            //      * WordFeatureExtractor: NgramLength = 1
            //      * CharFeatureExtractor: NgramLength = 3, UseAllLengths = false
            // The length of the output feature vector depends on these settings.
            var textPipeline = mlContext.Transforms.Text.FeaturizeText("Features",
                "Text");

            // Fit to data.
            var textTransformer = textPipeline.Fit(dataview);

            // Create the prediction engine to get the features extracted from the
            // text.
            var predictionEngine = mlContext.Model.CreatePredictionEngine<TextData,
                TransformedTextData>(textTransformer);

            // Convert the text into numeric features.
            var prediction = predictionEngine.Predict(samples[0]);

            // Print the length of the feature vector.
            Console.WriteLine($"Number of Features: {prediction.Features.Length}");

            // Print the first 10 feature values.
            Console.Write("Features: ");
            for (int i = 0; i < 10; i++)
                Console.Write($"{prediction.Features[i]:F4}  ");

            //  Expected output:
            //   Number of Features: 332
            //   Features: 0.0857  0.0857  0.0857  0.0857  0.0857  0.0857  0.0857  0.0857  0.0857  0.1715 ...
        }

        private class TextData
        {
            public string Text { get; set; }
        }

        private class TransformedTextData : TextData
        {
            public float[] Features { get; set; }
        }
    }
}

FeaturizeText(TransformsCatalog+TextTransforms, String, TextFeaturizingEstimator+Options, String[])

创建一个 TextFeaturizingEstimator，它将文本列转换为特征化向量 Single ，表示 n 元克和字符克的规范化计数。

public static Microsoft.ML.Transforms.Text.TextFeaturizingEstimator FeaturizeText (this Microsoft.ML.TransformsCatalog.TextTransforms catalog, string outputColumnName, Microsoft.ML.Transforms.Text.TextFeaturizingEstimator.Options options, params string[] inputColumnNames);

static member FeaturizeText : Microsoft.ML.TransformsCatalog.TextTransforms * string * Microsoft.ML.Transforms.Text.TextFeaturizingEstimator.Options * string[] -> Microsoft.ML.Transforms.Text.TextFeaturizingEstimator

<Extension()>
Public Function FeaturizeText (catalog As TransformsCatalog.TextTransforms, outputColumnName As String, options As TextFeaturizingEstimator.Options, ParamArray inputColumnNames As String()) As TextFeaturizingEstimator

参数

catalog

TransformsCatalog.TextTransforms

与文本相关的转换的目录。

outputColumnName

String

由转换 inputColumnNames生成的列的名称。 此列的数据类型将是一 Single个向量。

options

TextFeaturizingEstimator.Options

算法的高级选项。

inputColumnNames

String[]

要转换的列的名称。 If set to null, the value of the outputColumnName will be used as source. 此估算器对文本数据进行操作，并且可以一次转换多个列，从而生成一个作为所有列的结果特征的向量 Single 。

返回

TextFeaturizingEstimator

示例

using System;
using System.Collections.Generic;
using Microsoft.ML;
using Microsoft.ML.Transforms.Text;

namespace Samples.Dynamic
{
    public static class FeaturizeTextWithOptions
    {
        public static void Example()
        {
            // Create a new ML context, for ML.NET operations. It can be used for
            // exception tracking and logging, as well as the source of randomness.
            var mlContext = new MLContext();

            // Create a small dataset as an IEnumerable.
            var samples = new List<TextData>()
            {
                new TextData(){ Text = "ML.NET's FeaturizeText API uses a " +
                "composition of several basic transforms to convert text into " +
                "numeric features." },

                new TextData(){ Text = "This API can be used as a featurizer to " +
                "perform text classification." },

                new TextData(){ Text = "There are a number of approaches to text " +
                "classification." },

                new TextData(){ Text = "One of the simplest and most common " +
                "approaches is called “Bag of Words”." },

                new TextData(){ Text = "Text classification can be used for a " +
                "wide variety of tasks" },

                new TextData(){ Text = "such as sentiment analysis, topic " +
                "detection, intent identification etc." },
            };

            // Convert training data to IDataView.
            var dataview = mlContext.Data.LoadFromEnumerable(samples);

            // A pipeline for converting text into numeric features.
            // The following call to 'FeaturizeText' instantiates
            // 'TextFeaturizingEstimator' with given parameters. The length of the
            // output feature vector depends on these settings.
            var options = new TextFeaturizingEstimator.Options()
            {
                // Also output tokenized words
                OutputTokensColumnName = "OutputTokens",
                CaseMode = TextNormalizingEstimator.CaseMode.Lower,
                // Use ML.NET's built-in stop word remover
                StopWordsRemoverOptions = new StopWordsRemovingEstimator.Options()
                {
                    Language = TextFeaturizingEstimator.Language.English
                },

                WordFeatureExtractor = new WordBagEstimator.Options()
                {
                    NgramLength
                    = 2,
                    UseAllLengths = true
                },

                CharFeatureExtractor = new WordBagEstimator.Options()
                {
                    NgramLength
                    = 3,
                    UseAllLengths = false
                },
            };
            var textPipeline = mlContext.Transforms.Text.FeaturizeText("Features",
                options, "Text");

            // Fit to data.
            var textTransformer = textPipeline.Fit(dataview);

            // Create the prediction engine to get the features extracted from the
            // text.
            var predictionEngine = mlContext.Model.CreatePredictionEngine<TextData,
                TransformedTextData>(textTransformer);

            // Convert the text into numeric features.
            var prediction = predictionEngine.Predict(samples[0]);

            // Print the length of the feature vector.
            Console.WriteLine($"Number of Features: {prediction.Features.Length}");

            // Print feature values and tokens.
            Console.Write("Features: ");
            for (int i = 0; i < 10; i++)
                Console.Write($"{prediction.Features[i]:F4}  ");

            Console.WriteLine("\nTokens: " + string.Join(",", prediction
                .OutputTokens));

            //  Expected output:
            //   Number of Features: 282
            //   Features: 0.0941  0.0941  0.0941  0.0941  0.0941  0.0941  0.0941  0.0941  0.0941  0.1881 ...
            //   Tokens: ml.net's,featurizetext,api,uses,composition,basic,transforms,convert,text,numeric,features.
        }

        private class TextData
        {
            public string Text { get; set; }
        }

        private class TransformedTextData : TextData
        {
            public float[] Features { get; set; }
            public string[] OutputTokens { get; set; }
        }
    }
}

注解

此转换可以对多个列进行操作。