For smaller inputs and/or just one transformation Enum will be faster. For larger inputs with multiple transformations, using streams in the middle can sometimes be dramatically faster because we don’t generate large intermediate lists. More importantly, memory usage will be stable, thus reducing the chance of blowing up the production for some unexpected large input. That’s why I usually write a transformation pipeline in the style of:
input_enumerable
|> Stream.trans_1
|> Stream.trans_2
|> ...
|> Enum.last_trans
As always, there are some gotchas. If your code consumes an enumerable multiple times, it’s usually better to make sure that the input enumerable is not a stream, to avoid needless (and sometimes quite costly) duplicate computations.
