[Pharo-users] where are the nills come from and how do I get rid of them

[Roelof Wobben via Pharo-users]

Hello,

I have to make a word count from a sentence so I did this :
countWordsSentence: aString
    | splitted result |
    splitted := aString splitOn: [ :each | ', ' includes: each ].
    result := splitted
        inject: Bag new
        into: [ :wordBag :word |
            wordBag
                add: word;
                yourself ].
    ^ result valuesAndCounts

but now I see that the Bag is containing nills.
I tried to delete them by doing this :   cleaned := result reject: 
[:each | each isNil]

but to my surprise the nills are still there,
Why is that happening and what is the best way to delete them ?

Roelof