On 11 November 2016 at 12:02, stepharo <stepharo@free.fr> wrote:

String>>#isIsogram
�� | letters |
�� letters := Dictionary new.
�� self do: [ :x | letters at: x ifAbsent: [] ifPresent: [ ^false ].

Yes I did that one too and I was surprised because it was as slow as the bag implementation.

Anyone tried replacing the dictionary with an array of 26 booleans and indexing based on ascii, or even a SmallInteger and bit shifting?