DataOperationsCatalog.CrossValidationSplit Metode
Definisi
Penting
Beberapa informasi terkait produk prarilis yang dapat diubah secara signifikan sebelum dirilis. Microsoft tidak memberikan jaminan, tersirat maupun tersurat, sehubungan dengan informasi yang diberikan di sini.
Pisahkan himpunan data menjadi lipatan validasi silang kumpulan pelatihan dan set pengujian.
samplingKeyColumnName
Menghormati jika disediakan.
public System.Collections.Generic.IReadOnlyList<Microsoft.ML.DataOperationsCatalog.TrainTestData> CrossValidationSplit (Microsoft.ML.IDataView data, int numberOfFolds = 5, string samplingKeyColumnName = default, int? seed = default);
member this.CrossValidationSplit : Microsoft.ML.IDataView * int * string * Nullable<int> -> System.Collections.Generic.IReadOnlyList<Microsoft.ML.DataOperationsCatalog.TrainTestData>
Public Function CrossValidationSplit (data As IDataView, Optional numberOfFolds As Integer = 5, Optional samplingKeyColumnName As String = Nothing, Optional seed As Nullable(Of Integer) = Nothing) As IReadOnlyList(Of DataOperationsCatalog.TrainTestData)
Parameter
- data
- IDataView
Himpunan data yang akan dipisahkan.
- numberOfFolds
- Int32
Jumlah lipatan validasi silang.
- samplingKeyColumnName
- String
Nama kolom yang akan digunakan untuk mengelompokkan baris. Jika dua contoh memiliki nilai yang sama dari samplingKeyColumnName
, mereka dijamin akan muncul di subset yang sama (latih atau uji). Ini dapat digunakan untuk memastikan tidak ada kebocoran label dari kereta ke set pengujian.
Perhatikan bahwa saat melakukan Eksperimen Peringkat, samplingKeyColumnName
harus berupa kolom GroupId.
Jika null
tidak ada pengelompokan baris yang akan dilakukan.
Nilai awal untuk generator angka acak yang digunakan untuk memilih baris untuk lipatan validasi silang.
Mengembalikan
Contoh
using System;
using System.Collections.Generic;
using Microsoft.ML;
namespace Samples.Dynamic
{
/// <summary>
/// Sample class showing how to use CrossValidationSplit.
/// </summary>
public static class CrossValidationSplit
{
public static void Example()
{
// Creating the ML.Net IHostEnvironment object, needed for the pipeline.
var mlContext = new MLContext();
// Generate some data points.
var examples = GenerateRandomDataPoints(10);
// Convert the examples list to an IDataView object, which is consumable
// by ML.NET API.
var dataview = mlContext.Data.LoadFromEnumerable(examples);
// Cross validation splits your data randomly into set of "folds", and
// creates groups of Train and Test sets, where for each group, one fold
// is the Test and the rest of the folds the Train. So below, we specify
// Group column as the column containing the sampling keys. If we pass
// that column to cross validation it would be used to break data into
// certain chunks.
var folds = mlContext.Data
.CrossValidationSplit(dataview, numberOfFolds: 3,
samplingKeyColumnName: "Group");
var trainSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[0].TrainSet,
reuseRowObject: false);
var testSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[0].TestSet,
reuseRowObject: false);
PrintPreviewRows(trainSet, testSet);
// The data in the Train split.
// [Group, 1], [Features, 0.8173254]
// [Group, 2], [Features, 0.7680227]
// [Group, 1], [Features, 0.2060332]
// [Group, 2], [Features, 0.5588848]
// [Group, 1], [Features, 0.4421779]
// [Group, 2], [Features, 0.9775497]
//
// The data in the Test split.
// [Group, 0], [Features, 0.7262433]
// [Group, 0], [Features, 0.5581612]
// [Group, 0], [Features, 0.9060271]
// [Group, 0], [Features, 0.2737045]
trainSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[1].TrainSet,
reuseRowObject: false);
testSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[1].TestSet,
reuseRowObject: false);
PrintPreviewRows(trainSet, testSet);
// The data in the Train split.
// [Group, 0], [Features, 0.7262433]
// [Group, 2], [Features, 0.7680227]
// [Group, 0], [Features, 0.5581612]
// [Group, 2], [Features, 0.5588848]
// [Group, 0], [Features, 0.9060271]
// [Group, 2], [Features, 0.9775497]
// [Group, 0], [Features, 0.2737045]
//
// The data in the Test split.
// [Group, 1], [Features, 0.8173254]
// [Group, 1], [Features, 0.2060332]
// [Group, 1], [Features, 0.4421779]
trainSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[2].TrainSet,
reuseRowObject: false);
testSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[2].TestSet,
reuseRowObject: false);
PrintPreviewRows(trainSet, testSet);
// The data in the Train split.
// [Group, 0], [Features, 0.7262433]
// [Group, 1], [Features, 0.8173254]
// [Group, 0], [Features, 0.5581612]
// [Group, 1], [Features, 0.2060332]
// [Group, 0], [Features, 0.9060271]
// [Group, 1], [Features, 0.4421779]
// [Group, 0], [Features, 0.2737045]
//
// The data in the Test split.
// [Group, 2], [Features, 0.7680227]
// [Group, 2], [Features, 0.5588848]
// [Group, 2], [Features, 0.9775497]
// Example of a split without specifying a sampling key column.
folds = mlContext.Data.CrossValidationSplit(dataview, numberOfFolds: 3);
trainSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[0].TrainSet,
reuseRowObject: false);
testSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[0].TestSet,
reuseRowObject: false);
PrintPreviewRows(trainSet, testSet);
// The data in the Train split.
// [Group, 0], [Features, 0.7262433]
// [Group, 1], [Features, 0.8173254]
// [Group, 2], [Features, 0.7680227]
// [Group, 0], [Features, 0.5581612]
// [Group, 1], [Features, 0.2060332]
// [Group, 1], [Features, 0.4421779]
// [Group, 2], [Features, 0.9775497]
// [Group, 0], [Features, 0.2737045]
//
// The data in the Test split.
// [Group, 2], [Features, 0.5588848]
// [Group, 0], [Features, 0.9060271]
trainSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[1].TrainSet,
reuseRowObject: false);
testSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[1].TestSet,
reuseRowObject: false);
PrintPreviewRows(trainSet, testSet);
// The data in the Train split.
// [Group, 2], [Features, 0.7680227]
// [Group, 0], [Features, 0.5581612]
// [Group, 1], [Features, 0.2060332]
// [Group, 2], [Features, 0.5588848]
// [Group, 0], [Features, 0.9060271]
// [Group, 1], [Features, 0.4421779]
//
// The data in the Test split.
// [Group, 0], [Features, 0.7262433]
// [Group, 1], [Features, 0.8173254]
// [Group, 2], [Features, 0.9775497]
// [Group, 0], [Features, 0.2737045]
trainSet = mlContext.Data
.CreateEnumerable<DataPoint>(folds[2].TrainSet,
reuseRowObject: false);
testSet = mlContext.Data.CreateEnumerable<DataPoint>(folds[2].TestSet,
reuseRowObject: false);
PrintPreviewRows(trainSet, testSet);
// The data in the Train split.
// [Group, 0], [Features, 0.7262433]
// [Group, 1], [Features, 0.8173254]
// [Group, 2], [Features, 0.5588848]
// [Group, 0], [Features, 0.9060271]
// [Group, 2], [Features, 0.9775497]
// [Group, 0], [Features, 0.2737045]
//
// The data in the Test split.
// [Group, 2], [Features, 0.7680227]
// [Group, 0], [Features, 0.5581612]
// [Group, 1], [Features, 0.2060332]
// [Group, 1], [Features, 0.4421779]
}
private static IEnumerable<DataPoint> GenerateRandomDataPoints(int count,
int seed = 0)
{
var random = new Random(seed);
for (int i = 0; i < count; i++)
{
yield return new DataPoint
{
Group = i % 3,
// Create random features that are correlated with label.
Features = (float)random.NextDouble()
};
}
}
// Example with features and group column. A data set is a collection of
// such examples.
private class DataPoint
{
public float Group { get; set; }
public float Features { get; set; }
}
// print helper
private static void PrintPreviewRows(IEnumerable<DataPoint> trainSet,
IEnumerable<DataPoint> testSet)
{
Console.WriteLine($"The data in the Train split.");
foreach (var row in trainSet)
Console.WriteLine($"{row.Group}, {row.Features}");
Console.WriteLine($"\nThe data in the Test split.");
foreach (var row in testSet)
Console.WriteLine($"{row.Group}, {row.Features}");
}
}
}
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