Added describe method for numeric dataframes

Author: Joshua-Dias-Barreto

src/DataFrame-Tests/DataFrameTest.class.st

@@ -1553,6 +1553,26 @@ DataFrameTest >> testDataTypesWithNil [
 	self assert: df dataTypes equals: expected
 ]
 
+{ #category : #tests }
+DataFrameTest >> testDescribe [
+
+	| dataFrame expected |
+	dataFrame := DataFrame
+		             withRows: #( #( 1 1 ) #( 2 nil ) #( 3 1 ) )
+		             columnNames: #( 'A' 'B' ).
+
+	expected := DataFrame withRows:
+		            #( #( 3 2 1 1 1 2 3 3 SmallInteger )
+		               #( 2 1 0 1 1 1 1 1 SmallInteger ) ).
+
+	expected rowNames: #( 'A' 'B' ).
+	expected columnNames:
+		#( 'count' 'mean' 'std' 'min' '25%' '50%' '75%' 'max' 'dtype' ).
+	expected at: 1 at: 9 put: SmallInteger.
+	expected at: 2 at: 9 put: SmallInteger.
+	self assert: dataFrame describe equals: expected
+]
+
 { #category : #tests }
 DataFrameTest >> testDetect [
 	| actual expected |

src/DataFrame/DataFrame.class.st

@@ -942,6 +942,51 @@ DataFrame >> defaultHeadTailSize [
 	^ 5
 ]
 
+{ #category : #statistics }
+DataFrame >> describe [
+	"method to statistically describe a numerical dataframe"
+
+	| nCol nRow describeDF col count dtype |
+	nCol := self numberOfColumns.
+	nRow := self numberOfRows.
+	describeDF := self class new: nCol @ 9.
+	describeDF columnNames:
+		#( 'count' 'mean' 'std' 'min' '25%' '50%' '75%' 'max' 'dtype' ).
+	describeDF rowNames: self columnNames.
+	1 to: nCol do: [ :i |
+		| mean std mini fQ sQ tQ maxi |
+		col := self columnAt: i.
+		count := col countNonNils.
+		count = 0 ifFalse: [
+			col := col removeNils.
+			mean := col average.
+			std := col stdev.
+			mini := col min.
+			fQ := col firstQuartile.
+			sQ := col secondQuartile.
+			tQ := col thirdQuartile.
+			maxi := col max ].
+		dtype := col calculateDataType.
+		describeDF at: i at: 1 put: count.
+
+		describeDF at: i at: 2 put: mean.
+
+		describeDF at: i at: 3 put: std.
+
+		describeDF at: i at: 4 put: mini.
+
+		describeDF at: i at: 5 put: fQ.
+
+		describeDF at: i at: 6 put: sQ.
+
+		describeDF at: i at: 7 put: tQ.
+
+		describeDF at: i at: 8 put: maxi.
+
+		describeDF at: i at: 9 put: dtype ].
+	^ describeDF
+]
+
 { #category : #accessing }
 DataFrame >> dimensions [
 	"Returns the number of rows and number of columns in a DataFrame"