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Python Python Collections (Retired) Tuples Combo

Frank Sherlotti
PLUS
Frank Sherlotti
Courses Plus Student 1,952 Points
Posted by Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points

Combo challenge: Please help.

QUESTION -- Create a function named combo() that takes two iterables and returns a list of tuples. Each tuple should hold the first item in each list, then the second set, then the third, and so on. Assume the iterables will be the same length. I've been messing with this for a few days now and I've made no headway and it's infuriating me. I was wondering if someone could just give me the answer at this point, or just give me obvious hints to what the answer is. Really do appreciate anyone who does decide to help, thanks!!

combo(['swallow', 'snake', 'parrot'], 'abc')

Output:

[('swallow', 'a'), ('snake', 'b'), ('parrot', 'c')]

If you use list.append(), you'll want to pass it a tuple of new values.

Using enumerate() here can save you a variable or two.

def combo(first, second):
  empty = ()
  for index, value in enumerate(first):
    empty = first
    empty.append(second)
  return empty

2 Answers

Anish Walawalkar
Anish Walawalkar
8,534 Points
Anish Walawalkar
Anish Walawalkar
8,534 Points

You can use the zip(first, second). this will return a list of tuples. that will solve your problem

return zip(first, second)

this will also fix your problem:

def combo(item1, item2):
    x = []
    for index, item in enumerate(item2):           
        x.append((item1[index], item))
    return x
Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points
Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points

Which would be the correct way to do it so I know for future reference. And also THANK YOU VERY MUCH! You have no idea how much that helps me out I really do appreciate it.

Anish Walawalkar
Anish Walawalkar
8,534 Points
Anish Walawalkar
Anish Walawalkar
8,534 Points

Well its always better to use an inbuilt language feature. So using the zip() function is a better way of doing it.

Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points
Frank Sherlotti
Frank Sherlotti
Courses Plus Student 1,952 Points

What's the difference between for index, item and for index, value? And would the return zip(first, second) way look like this? I don't see how this zip method works.

def combo(first, second):
  empty = ()
  for index, value in enumerate(first):
    empty = first
    empty.append(second)
  return zip(first, second)
Anish Walawalkar
Anish Walawalkar
8,534 Points
Anish Walawalkar
Anish Walawalkar
8,534 Points

Say you have a list of names:

names = ['Frank', 'John', 'Anish']

so when you do:

for index, value in enumerate(names):

enumerate returns a tuple of (index, value) for each element of the list. for example when the for loop runs the first time, the enumerate(names) function returns (0, 'Frank') which gets stored as index=0 and value = 'Frank'

so finally to answer your first question: NO there is not difference b/w for index, value and for index, item

Now for your second question: you do not need to run a for loop. zip(first, second) is an inbuilt python function that handles what the for loop is doing internally. So if you were to use the zip(first, second) your function should look like this:

def combof(first, second):
    return zip(first, second)

Hope this answers your question. Anish