ch5-5.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Fri Jan 15 17:15:57 2021

@author: HMFR
"""
"""
sets: unordered list, duplicates are removed
make by {'element1',...,'','',''}
to make an empty one use set()


"""

basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
print(basket)                      # show that duplicates have been removed

'orange' in basket                 # fast membership testing

'crabgrass' in basket

'''
# Demonstrate set operations on unique letters from two words

a = set('abracadabra')
b = set('alacazam')
a                                  # unique letters in a

a - b                              # letters in a but not in b

a | b                              # letters in a or b or both

a & b                              # letters in both a and b

a ^ b                              # letters in a or b but not both
'''


#set comprehensions
a = {x for x in 'abracadabra' if x not in 'abc'}