str

No

Yes

You want to keep track of text.

list

Yes

Yes

You want to keep track of an ordered sequence that you want to update.

tuple

No

Yes

You want to build an ordered sequence that you know won’t change or that you want to use as a key in a dictionary or as a value in a set.

set

Yes

No

You want to keep track of values, but order doesn’t matter, and you don’t want to keep duplicates. The values must be immutable.

dictionary

Yes

No

You want to keep a mapping of keys to values. The keys must be immutable.