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Python Python Collections (Retired) Tuples Combo

Sahar Nasiri
Sahar Nasiri
7,454 Points
Posted by Sahar Nasiri
Sahar Nasiri
7,454 Points

Why do I get an error?

def combo(it_1, it_2): l = [] d = {} for item_1 in it_1: for item_2 in it_2: if (item_1 not in d.keys()) and (item_2 not in d.values()): d[item_1] = item_2
for key, value in d.items(): l.append((key, value)) return l print(combo([1, 2, 3], 'abc'))

zippy.py 
# combo([1, 2, 3], 'abc')
# Output:
# [(1, 'a'), (2, 'b'), (3, 'c')]
# If you use .append(), you'll want to pass it a tuple of new values.
def combo(it_1, it_2):
  l = []
  d = {}
  for item_1 in it_1:
    for item_2 in it_2:
      if (item_1 not in d.keys()) and (item_2 not in d.values()):
        d[item_1] = item_2

  for key, value in d.items():
    l.append((key, value))
  return l
print(combo([1, 2, 3], 'abc'))

1 Answer

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,423 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,423 Points

There are two issues with your code:

  • if the order of the number is reversed, your code reorder them
>>> combo([3,2,1], 'abc')
[(1, 'c'), (2, 'b'), (3, 'a')]
  • if there is a repeating character on the right, it gets dropped
>>> combo([1,2,3,4,5,6], 'abfdef')
[(1, 'a'), (2, 'b'), (3, 'f'), (4, 'd'), (5, 'e')]

Here are some alternate solutions to compare to:

def combo(itr1, itr2):
    tup_list = list()
    for index, num in enumerate(itr1):
        a = num
        b = itr2[index]

        new_tup = a, b
        tup_list.append(new_tup)
    return tup_list


def combo(itr1, itr2):
    tup_list = list()
    for num, letter in zip(itr1, itr2):
        a = num
        b = letter

        new_tup = a, b
        tup_list.append(new_tup)
    return tup_list


def combo(itr1, itr2):
    # this can be shortened to:
    tup_list = list()
    for index, num in enumerate(itr1):
        tup_list.append((num, itr2[index]))
    return tup_list


def combo(itr1, itr2):
    tup_list = list()
    for num, letter in zip(itr1, itr2):
        tup_list.append((num, letter))
    return tup_list


# the last one can be shortened even further
# since 'zip' returns a the one entry from each list as a tuple
def combo(itr1, itr2):
    tup_list = list(zip(itr1, itr2))
    return tup_list
Sahar Nasiri
Sahar Nasiri
7,454 Points
Sahar Nasiri
Sahar Nasiri
7,454 Points

The answers were really helpful, thanks. :)