Difference between sets and dictionaries in python ???

Answer 1

Take a brief description:
https://www.sololearn.com/learn/JUMP_LINK__&&__Python__&&__JUMP_LINK/2464/
https://www.sololearn.com/learn/Python/2450/

Basically, sets are just containers of *unique* elements, while dictionaries - of unique key-value pairs.

Answer 2

You use sets if you do not want duplicates for example s={1, 3, 6, 6, 7} is the same as s={1, 3, 6, 7} and the elements of a set are not indexed which means that s[2] for example will produce an error .