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Python Python Collections (Retired) Tuples Combo

Posted by Kristinn Godfrey
Kristinn Godfrey
6,161 Points

I'm 99% sure there's nothing wrong with my tuples solution

Hey my following code gets the error: "Bummer! Didn't get the right output. For example, expected (10, 'T') as the first item, got (10, 'T') instead."

That's the same value!

I already got it right by replacing my iteration from tuples indexes to "n" index.

Is there something wrong with doing it this way?

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(some_list, some_string):
  new_list = []
  for n in range(len(some_string)):
    new_list.append((some_list[0],some_string[0]))
  return new_list

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

Running your code interactively shows the issue:

$ python3
Python 3.4.0 (default, Jun 19 2015, 14:20:21) 
[GCC 4.8.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> def combo(some_list, some_string):
...   new_list = []
...   for n in range(len(some_string)):
...     new_list.append((some_list[0],some_string[0]))
...   return new_list
... 
>>> combo([1,2,3,4,5,6], "abcdef")
[(1, 'a'), (1, 'a'), (1, 'a'), (1, 'a'), (1, 'a'), (1, 'a')]

You need change the index to n instead of the fixed 0:

...     new_list.append((some_list[n],some_string[n]))
Kristinn Godfrey
Kristinn Godfrey
6,161 Points

Thanks, I'm on a crossroads of new information, thought 0 there wasn't a fixed size

Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

The index notation of [0] means the first element ("the zero-th")

Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

You could also write your loop in a different way so that you don't have to worry abut the index:

def combo(some_list, some_string):
    new_list = []
    for item, letter in zip(some_list, some_string):
        new_list.append((item, letter))
    return new_list
``
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,441 Points

Nice! If you're going to use zip go all the way. Since zip returns a list the for loop iteration becomes redundant.

def combo(some_list, some_string):
    new_list = list(zip(some_list, some_string))
    return new_list

# or simply
def combo(some_list, some_string):
    return list(zip(some_list, some_string))
Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

That's awesome! Thanks for the tip Chris Freeman !