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Python Python Collections (2016, retired 2019) Tuples Combo

fahad lashari
fahad lashari
7,693 Points
Posted by fahad lashari
fahad lashari
7,693 Points

Don't know of any alternative to zip(). Any help?

The last time I completed this track. I used the zip() function to iterate through two loops simultaneously. I am however not aware of how to achieve this in an alternative matter. Any help would be much appreciated.

Kind regards,

Fahad

combo.py 
# combo([1, 2, 3], 'abc')
# Output:
# [(1, 'a'), (2, 'b'), (3, 'c')]
def combo(list1, list2):
    list = []
    for i, j in zip(list1, list2):
            list.append((i, j))
    return list

1 Answer

Alexander Davison
Alexander Davison
65,469 Points

Kenneth put a little change on this code challenge that makes you so you can't use zip.

If you can't think of another way, you can only loop through the indexes of the first/second list. Then you use those indices to get the element at the same indices on both lists.

def combo(iter1, iter2):
    result = []
    for index in range(len(iter1)):
        result.append((iter1[index], iter2[index]))
    return result

What I'm doing:

  1. I set up the function definition and the result variable to be an empty list.
  2. I go though every index of the first iterable. (It doesn't matter if it's the first or the second, because the challenge said they will be the same length)
  3. I add a pair (a tuple with two items is sometimes called a pair) with the first element to be the first iterable's index index and the second element to be the second iterable's index index.
  4. I finally return the result list. (duh)

You sometimes have to think what you would do if you had to solve it without a computer then do that on the computer.

I hope this helps. ~Alex

Alexey Serpuhovitov
Alexey Serpuhovitov
6,931 Points
Alexey Serpuhovitov
Alexey Serpuhovitov
6,931 Points

Alex, could you explain, why we need

for index in range(len(iter1)):

pattern and not just 

for index in iter1:
Alexander Davison
Alexander Davison
65,469 Points 
for index in iter1

Will loop through every item in iter1, and

for index in range(len(iter1))

Will go through every index.

If we enter this into both loops...

print(index)

The first loop will print this (if iter1 was the list ['a', 'b', 'c']):

a
b
c

The second loop will print:

0
1
2
Joshua Dam
Joshua Dam
7,148 Points
Joshua Dam
Joshua Dam
7,148 Points

Yeah, that works! You could also use the enumerate() function! I only bring that up because Kenneth covers enumerate() within the tuples section of the course just before this challenge.

def combo(iter1, iter2):
    result = []
    for index, value in enumerate(iter1):
        result.append((iter1[index], iter2[index]))
    return result

combo('abc', '123')