#columns now returns an array of Dataseries. Changed the implementation of #hasNils as it used #columns

Author: Joshua-Dias-Barreto

src/DataFrame-Tests/DataFrameTest.class.st

@@ -758,11 +758,10 @@ DataFrameTest >> testColumnTransformNotFound [
 DataFrameTest >> testColumns [
 
 	| expectedCollection |
-
-	expectedCollection := #(
-		(Barcelona Dubai London)
-	   (1.609 2.789 8.788)
-	   (true true false)).
+	expectedCollection := {
+		                      (df columnAt: 1).
+		                      (df columnAt: 2).
+		                      (df columnAt: 3) } asArray.
 
 	self assert: df columns equals: expectedCollection
 ]

src/DataFrame/DataFrame.class.st

@@ -722,10 +722,9 @@ DataFrame >> columnNames: aCollection [
 
 { #category : #accessing }
 DataFrame >> columns [
-
 	"Returns a collection of all columns"
 
-	^ self asArrayOfColumns
+	^ (1 to: self numberOfColumns) collect: [ :j | self columnAt: j ]
 ]
 
 { #category : #accessing }
@@ -1054,9 +1053,7 @@ DataFrame >> hasNils [
 
 	| arrayOfColumns |
 	arrayOfColumns := self columns.
-	1 to: self numberOfColumns do: [ :column |
-		1 to: self numberOfRows do: [ :row |
-		((arrayOfColumns at: column) at: row) ifNil: [ ^ true ] ] ].
+	arrayOfColumns collect: [ :column | column hasNil ifTrue: [ ^ true ] ].
 	^ false
 ]