Fixed #222 . Added DataSeries>> #encodeOneHot.

Author: Joshua-Dias-Barreto

src/DataFrame-Tests/DataSeriesTest.class.st

@@ -1273,6 +1273,52 @@ DataSeriesTest >> testEighth [
 	self assert: series eighth equals: 10
 ]
 
+{ #category : #'tests - converting' }
+DataSeriesTest >> testEncodeOneHot [
+
+	| actual expected |
+	actual := #( 1 2 3 4 ) asDataSeries encodeOneHot.
+	expected := #(
+	    #(1 0 0 0)
+	    #(0 1 0 0)
+	    #(0 0 1 0)
+		 #(0 0 0 1)
+	) asDataSeries.
+
+	self assert: actual equals: expected
+]
+
+{ #category : #'tests - converting' }
+DataSeriesTest >> testEncodeOneHotRomanNumbers [
+
+	| actual expected |
+	actual := (#( I XIV VII XXXII ) collect: [ :each | each romanNumber ])
+		          asDataSeries encodeOneHot.
+	expected := #(
+	    #(1 0 0 0)
+	    #(0 0 1 0)
+	    #(0 1 0 0)
+		 #(0 0 0 1)
+	) asDataSeries.
+
+	self assert: actual equals: expected
+]
+
+{ #category : #'tests - converting' }
+DataSeriesTest >> testEncodeOneHotStrings [
+
+	| actual expected |
+	actual := #( apple avocado orange banana ) asDataSeries encodeOneHot.
+	expected := #(
+	    #(1 0 0 0)
+	    #(0 1 0 0)
+	    #(0 0 0 1)
+		 #(0 0 1 0)
+	) asDataSeries.
+
+	self assert: actual equals: expected
+]
+
 { #category : #'tests - comparing' }
 DataSeriesTest >> testEquality [
 

src/DataFrame/DataSeries.class.st

@@ -319,6 +319,25 @@ DataSeries >> eighth [
 	^ self atIndex: 8
 ]
 
+{ #category : #converting }
+DataSeries >> encodeOneHot [
+	"Encode the values of the DataSeries into one-hot vectors."
+
+	| uniqueValues encodingDataSeries oneHotValues |
+	uniqueValues := self removeDuplicates sortIfPossible.
+	encodingDataSeries := DataSeries new.
+	uniqueValues withIndexDo: [ :value :index |
+		encodingDataSeries at: value put: index ].
+	oneHotValues := self values collect: [ :value |
+		                | oneHot |
+		                oneHot := encodingDataSeries keys collect: [ :key |
+			                          value = key
+				                          ifTrue: [ 1 ]
+				                          ifFalse: [ 0 ] ].
+		                oneHot ].
+	^ DataSeries withKeys: self keys values: oneHotValues name: self name
+]
+
 { #category : #private }
 DataSeries >> errorKeyNotFound: aKey [