Added comments

Author: josh0306

src/DataFrame/DataFrame.class.st

@@ -783,7 +783,8 @@ DataFrame >> columnsFrom: firstNumber to: secondNumber put: anArrayOfArrays [
 
 { #category : #accessing }
 DataFrame >> contents [
-
+	"Returns all the values of the DataFrame"
+	
 	^ contents
 ]
 
@@ -970,11 +971,14 @@ DataFrame >> getJointColumnsWith: aDataFrame [
 
 { #category : #grouping }
 DataFrame >> group: anAggregateColumnName by: aGroupColumnName aggregateUsing: aBlock [
+	"Group the values of the cloumn named anAggregateColumnName by the unique values of the column named aGroupColumnName, aggregate them using aBlock. With the same name as anAggregateColumnName"
+	
 	^ self group: anAggregateColumnName by: aGroupColumnName aggregateUsing: aBlock as: anAggregateColumnName
 ]
 
 { #category : #grouping }
 DataFrame >> group: anAggregateColumnName by: aGroupColumnName aggregateUsing: aBlock as: aNewColumnName [
+	"Group the values of the cloumn named anAggregateColumnName by the unique values of the column named aGroupColumnName, aggregate them using aBlock. With a new column name aNewColumnName"
 
 	| groupColumn aggregateColumn |
 

src/DataFrame/DataSeries.class.st

@@ -697,11 +697,15 @@ DataSeries >> sortDescending [
 
 { #category : #sorting }
 DataSeries >> sorted [
+	"Returns a sorted copy of the data series without rearranging the original data series"
+	
 	^ self sorted: [ :a :b | a <= b ]
 ]
 
 { #category : #sorting }
 DataSeries >> sorted: aBlock [
+	"Returns a copy of the data series after applying aBlock without rearranging the original data series"
+
 	| associationBlock |
 	associationBlock := [ :a :b | aBlock value: a value value: b value ].
 	^ self sortedAssociations: associationBlock
@@ -716,6 +720,8 @@ DataSeries >> sortedAssociations: aBlock [
 
 { #category : #sorting }
 DataSeries >> sortedDescending [
+	"Returns a sorted copy of the data series in descending order without rearranging the original data series"
+
 	^ self sorted: [ :a :b | a > b ]
 ]
 
@@ -942,7 +948,8 @@ DataSeries >> withSeries: otherDataSeries collect: twoArgBlock [
 
 { #category : #private }
 DataSeries >> withoutNils [
-
+	"Returns a data series without the elements whose values were nil values"
+	
 	^ self reject: #isNil
 ]