Make sum behave like in Panda. If a data series contains nils, ignore them for the sum.

Author: jecisc

src/DataFrame-Tests/DataSeriesTest.class.st

@@ -2108,6 +2108,19 @@ DataSeriesTest >> testStatsZerothQuartileEqualsMin [
 	self assert: series zerothQuartile equals: series min
 ]
 
+{ #category : #'tests - arithmetic' }
+DataSeriesTest >> testSum [
+
+	self assert: #( 1 2 3 4 ) asDataSeries sum equals: 10
+]
+
+{ #category : #'tests - arithmetic' }
+DataSeriesTest >> testSumWithNils [
+
+	self assert: #( 1 2 nil 4 ) asDataSeries sum equals: 7.
+	self assert: #( nil nil nil ) asDataSeries sum equals: 0
+]
+
 { #category : #'tests - head/tail' }
 DataSeriesTest >> testTail [
 	| expected actual |

src/DataFrame/DataSeries.class.st

@@ -660,6 +660,13 @@ DataSeries >> sortedDescending [
 	^ self sorted: [ :a :b | a > b ]
 ]
 
+{ #category : #transformation }
+DataSeries >> sum [
+	"Return the sum of the values over the requested axis. Nil values are excluded."
+
+	^ (self reject: #isNil) inject: 0 into: [ :accum :each | accum + each ]
+]
+
 { #category : #statistics }
 DataSeries >> summary [
 	| summary |