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Python Python Collections (Retired) Tuples Combo

Craig Campbell
Craig Campbell
14,428 Points
Posted by Craig Campbell
Craig Campbell
14,428 Points

a better way to do combo() python challenge

I'm learning Python after having coded in JavaScript land. I always want to do something like this: for (var i =0; i > array.length; i++) { // some stuff} but thats not how Python works. I solved the combo challenge in Python Collections as below, but this definitely has an un-pythonic code smell as I'm trying to use JS type thinking. While my code works, I'd like a more elegant solution. Can someone share a better way to do this?

def combo(iter1, iter2):
  tup_list = []
  list1 = []
  list2 = []
  count = 0
  for thing in iter1:
    list1.append(thing)

  for thing in iter2:
    list2.append(thing)

    tup = tuple((list1[count], list2[count]))
    tup_list.append(tup)
    count +=1

  return tup_list

3 Answers

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

Let's deconstruct your code:

You can create a list from an iterable directly using list1 = list(iter1). but you need not create a list as you can operate directly on the iterable arguments

def combo(iter1, iter2):
  tup_list = []
  count = 0

  for thing in iter2:
    tup = tuple((iter1[count], iter2[count]))
    tup_list.append(tup)
    count +=1

  return tup_list

You can also generate the count directly from one of the iterables:

def combo(iter1, iter2):
  tup_list = []

  for count in range(iter1):
    tup = tuple((iter1[count], iter2[count]))
    tup_list.append(tup)

  return tup_list

For a more advanced solution, you can use the built-in zip function (covered later) that "zips" two iterables together by returning one item from each iterable as a tuple. Wrapping this in a list() provides the complete solution:

def combo(iter1, iter2):
  return list(zip(iter1, iter2))
Dillon Wyatt
Dillon Wyatt
5,990 Points
Dillon Wyatt
Dillon Wyatt
5,990 Points

Wow. That seems so much simpler than my solution. 

def combo(*args):
    new_list = []
    counter = 0
    subset1 = args[0]
    subset2 = args[1]
    maxer = len(subset1)
    while counter < maxer:
        a = subset1[counter],subset2[counter]
        new_list.append(a)
        counter +=1
    return(new_list)
combo([1, 2, 3], 'abc')

The above example seems more straightforward than my setup using a while loop.