set

The set is one of most powerful concepts in python. I recently watched following video

Slides are available at speakerdeck. Here are my notes from the watching

• the set is not mere container for unique elements
• there is many powerful operations working over whole sets
  • intersection works similarly to and, operator & in python
  • union is basically or, operator | in python
  • symmetric difference compares to xor, items in each sets, but not both, operator ^ in python
  • difference - things in first that are not in second, operator - in python
• way to build set from series - set comprehension
• set constructor from any iterable
• in operator is very fast (set is implemented as hash table)
• subset and superset comparisons with >= operators
• update methods (update add items from iterable, intersection_update intersects with iterable)
• the interface is defined in collections.abc, most of set operations are defined there
• praise for the book Go Programming Language by Alan Donovan and Brian Kernighan
• demonstration of writing alternate set of unsigned integers, available on github