Feature! collect: forms a new collection of the same kind as its receiver. In this case a set. As the result of your collect: #(1 2 3) asSet collect: #odd) is booleans, the resulting set will contain only to elements (the duplicate odd resulting in true is removed).
collect: thenDo: applies the collect-block to each element of the receiver, and then applies the do to each of those results. You can see the implementation of collect:thenDo: in class Collection. Best, Kasper On 7 September 2019 at 17.22.03, Herby Vojčík (he...@mailbox.sk) wrote: Hello! ---- (#(1 2 3) asSet collect: #odd) do: [ :each | Transcript show: each; cr ] > true > false ---- #(1 2 3) asSet collect: #odd thenDo: [ :each | Transcript show: each; cr ] > true > false > true ---- Bug or feature? Herby