You now know all four of Python's main collections. Choosing well makes code simpler and faster.

	Ordered	Duplicates	Changeable	Look up by
list `[ ]`	yes	yes	yes	position
tuple `( )`	yes	yes	no	position
set `{ }`	no	no	yes	membership only
dict `{k: v}`	by insertion	keys unique	yes	key

A few rules of thumb: