# some ways to translate between different collections:
#  dictionary, list, and set
# a dictionary can be represented as tuples of two items
>>> d = { 'a':13, 'b':4, 'c':245 }
>>> d
Out[49]: {'a': 13, 'b': 4, 'c': 245}
>>> d.items()
Out[50]: [('a', 13), ('c', 245), ('b', 4)]
# so a list can be used to create a dictionary
>>> l = [('h', 1), ('z', 2), ('a', 3)]
>>> l
Out[51]: [('h', 1), ('z', 2), ('a', 3)]
>>> dict(l)
Out[52]: {'a': 3, 'h': 1, 'z': 2}
# parallel lists can be turned into a dictionary easily
>>> a = [ 1, 2, 3, 4 ]
>>> b = [ 5, 6, 7, 8 ]
>>> zip(a, b)
Out[56]: [(1, 5), (2, 6), (3, 7), (4, 8)]
>>> dict(zip(a, b))
Out[57]: {1: 5, 2: 6, 3: 7, 4: 8}

# a set can be made from any collection (with immutable items)
>>> set('hello')
Out[58]: set(['h', 'e', 'l', 'o'])
>>> set(l)
Out[59]: set([('z', 2), ('a', 3), ('h', 1)])
>>> set(d.values())
Out[60]: set([4, 13, 245])
>>> d['c'] = 13
>>> set(d.values())
Out[61]: set([4, 13])