python学习记录--集合

old_dict = {'h1': 1,
            'h2': 2,
            'h3': 3}
new_dict = {'h1': 1,
            'h3': 3,
            'h4': 4}
old = set(old_dict.keys())
print(old_dict.keys())
print(old_dict.values())
print(old_dict.items())
new = set(new_dict.keys())
print(old, new)

update_set = old.intersection(new)
delete_set = old.symmetric_difference(update_set)
add_set = new.symmetric_difference(update_set)
print(delete_set, add_set)

#difference和symmetric_difference的区别
ret1 = old.difference(new)
ret2 = old.symmetric_difference(new)
print(ret1,ret2)