private static (DataFrame, string[]) BinaryEncoding2(this DataFrame df, string colName, bool encodedOnly = false)
{
var colVector = df[colName];
var classValues = colVector.Where(x => DataFrame.NAN != x).Select(x => x.ToString()).Distinct().ToList();
//define encoded columns
var dict = new Dictionary <string, List <object> >();
var encodedValues = new List <object>();
foreach (var value in colVector)
{
int ordinalValue = classValues.IndexOf(value.ToString());
if (ordinalValue == 0)
{
ordinalValue = -1;
}
encodedValues.Add(ordinalValue);
}
//
dict.Add(colName + "_cvalues", encodedValues);
var newDf = df.AddColumns(dict);
if (encodedOnly)
{
return(newDf[new string[] { colName + "_cvalues" }], classValues.ToArray());
}
else
{
return(newDf, classValues.ToArray());
}
}
public void AddSameColumns_Test01()
{
var dict = new Dictionary <string, List <object> >
{
{ "col1", new List <object>()
{
1, 11, 21, 31, 41, 51, 61, 71, 81, 91
} },
{ "col2", new List <object>()
{
2, 12, 22, 32, 42, 52, 62, 72, 82, 92
} },
{ "col3", new List <object>()
{
3, 13, 23, 33, 43, 53, 63, 73, 83, 93
} },
{ "col4", new List <object>()
{
4, 14, 24, 34, 44, 54, 64, 74, 84, 94
} },
{ "col5", new List <object>()
{
5, 15, 25, 35, 45, 55, 65, 75, 85, 95
} },
{ "col6", new List <object>()
{
6, 16, 26, 36, 46, 56, 66, 76, 86, 96
} },
{ "col7", new List <object>()
{
7, 17, 27, 37, 47, 57, 67, 77, 87, 97
} },
};
//
var df = new DataFrame(dict);
//define three new columns
var d = new Dictionary <string, List <object> >
{
{ "col5", new List <object>()
{
8, 18, 28, 38, 48, 58, 68, 78, 88, 98
} },
{ "col2", new List <object>()
{
9, 19, 29, 39, 49, 59, 69, 79, 89, 99
} },
{ "col10", new List <object>()
{
10, 20, 30, 40, 50, 60, 70, 80, 90, 100
} },
};
//exception the number of list object is not divisible with column counts
var exception = Assert.ThrowsAny <System.Exception>(() => df.AddColumns(d));
Assert.Equal("Column(s) 'col2, col5' already exist(s) in the data frame.", exception.Message);
}
public static DataFrame EncodeColumn(this DataFrame df, MLContext mlContext, string colName, bool encodedOnly = false)
{
var colVector = df[colName];
IDataView data = mlContext.Data.LoadFromEnumerable <CategoryColumn>(colVector.Select(x => new CategoryColumn()
{
Classes = x.ToString()
}));
var fitData = mlContext.Transforms.Categorical.OneHotEncoding(nameof(CategoryColumn.Classes)).Fit(data);
var transData = fitData.Transform(data);
//retrieve annotation from the column about slotnames
VBuffer <ReadOnlyMemory <char> > labels = default;
transData.Schema[nameof(CategoryColumn.Classes)].GetSlotNames(ref labels);
var convertedData = mlContext.Data.CreateEnumerable <EncodedColumn>(transData, true);
var originalLabels = labels.DenseValues().Select(x => x.ToString()).ToList();
var dict = new Dictionary <string, List <object> >();
foreach (var r in convertedData)
{
for (int i = 0; i < originalLabels.Count; i++)
{
if (!dict.ContainsKey(originalLabels[i]))
{
var lst = new List <object>();
lst.Add((object)r.Classes[i]);
dict.Add(originalLabels[i], lst);
}
else
{
dict[originalLabels[i]].Add((object)r.Classes[i]);
}
}
}
if (encodedOnly)
{
var newDf = new DataFrame(dict);
return(newDf);
}
else
{
var newDf = df.AddColumns(dict);
return(newDf);
}
}
private static (DataFrame, string[]) DummyEncodeColumn(this DataFrame df, string colName, bool encodedOnly = false)
{
var colVector = df[colName];
var classValues = colVector.Where(x => DataFrame.NAN != x).Select(x => x.ToString()).Distinct().ToArray();
//define encoded columns
var dict = new Dictionary <string, List <object> >();
var dummyClasses = classValues.SkipLast(1);
//add dummy encoded columns
foreach (var c in dummyClasses)
{
dict.Add(c, new List <object>());
}
//encode values
foreach (var cValue in colVector)
{
for (int i = 0; i < dummyClasses.Count(); i++)
{
if (cValue.ToString() == classValues[i])
{
dict[classValues[i]].Add((int)1);
}
else
{
dict[classValues[i]].Add((int)0);
}
}
}
if (encodedOnly)
{
var newDf = new DataFrame(dict);
return(newDf, classValues);
}
else
{
var newDf = df.AddColumns(dict);
return(newDf, classValues);
}
}
public static void CategoryToKey(this DataFrame df, MLContext mlContext, string colName)
{
var colVector = df[colName];
IDataView data = mlContext.Data.LoadFromEnumerable <CategoryColumn>(colVector.Select(x => new CategoryColumn()
{
Classes = x.ToString()
}));
var fitData = mlContext.Transforms.Categorical.OneHotEncoding(nameof(CategoryColumn.Classes), outputKind: OneHotEncodingEstimator.OutputKind.Key).Fit(data);
var transData = fitData.Transform(data);
var convertedData = mlContext.Data.CreateEnumerable <CategoryValues>(transData, true);
var dict = new Dictionary <string, List <object> >();
var colValues = new List <object>();
foreach (var r in convertedData)
{
colValues.Add(r.Classes);
}
dict.Add(colName + "_cvalues", colValues);
df.AddColumns(dict);
return;
}
public void AddColumns_Test01()
{
var dict = new Dictionary <string, List <object> >
{
{ "col1", new List <object>()
{
1, 11, 21, 31, 41, 51, 61, 71, 81, 91
} },
{ "col2", new List <object>()
{
2, 12, 22, 32, 42, 52, 62, 72, 82, 92
} },
{ "col3", new List <object>()
{
3, 13, 23, 33, 43, 53, 63, 73, 83, 93
} },
{ "col4", new List <object>()
{
4, 14, 24, 34, 44, 54, 64, 74, 84, 94
} },
{ "col5", new List <object>()
{
5, 15, 25, 35, 45, 55, 65, 75, 85, 95
} },
{ "col6", new List <object>()
{
6, 16, 26, 36, 46, 56, 66, 76, 86, 96
} },
{ "col7", new List <object>()
{
7, 17, 27, 37, 47, 57, 67, 77, 87, 97
} },
};
//
var df = new DataFrame(dict);
//define three new columns
var d = new Dictionary <string, List <object> >
{
{ "col8", new List <object>()
{
8, 18, 28, 38, 48, 58, 68, 78, 88, 98
} },
{ "col9", new List <object>()
{
9, 19, 29, 39, 49, 59, 69, 79, 89, 99
} },
{ "col10", new List <object>()
{
10, 20, 30, 40, 50, 60, 70, 80, 90, 100
} },
};
//add three new columns
var newDf = df.AddColumns(d);
Assert.Equal(7, df.ColCount());
Assert.Equal(10, newDf.ColCount());
for (int i = 0; i < newDf.Values.Count; i++)
{
Assert.Equal(i + 1, newDf.Values[i]);
}
}