Keep getting not all arguments converted during string formatting in python

Question

I keep getting error messages during line six and I am not sure why. It keeps saying that not all values are being converted during string formatting. I am trying to create a program that identifies a unique number out of a string of numbers.

   def iq_test(numbers):
        oddlist = []
        evenlist = []
        numbers = numbers.split()
        for x in numbers:
            if x % 2 == 0:
                evenlist.append(x)
            if x % 2 != 0:
                oddlist.append(x)
        if len(evenlist) > len(oddlist):
            return "".join(oddlist)
        else:
            return "".join(evenlist)

Answer 1

Python's split function returns a list of Strings. So every x value in your for loop is actually a String representation of whatever number x is. That means any arithmetic/numerical operation you perform on x will fail because you can't perform numerical operations on a String.

Simply do int(x) to cast any numerical String to an int . (ie int("3") % 2 == 1 )

Answer 2

It looks like this function is supposed to return the shorter list of even numbers or odd numbers from an input list. After your .split() the result is a list of strings, so the math is basically doing this:

>>> "1" % 2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: not all arguments converted during string formatting

Here's the fix:

def iq_test(numbers):
        oddlist = []
        evenlist = []

        # Splitting the input strings returns a list of strings.
        # Use a list comprehension to convert them to integers.
        numbers = [int(x) for x in numbers.split()]

        for x in numbers:
            if x % 2 == 0:
                evenlist.append(x)
            else: # Can just use an else here
                oddlist.append(x)
        if len(evenlist) > len(oddlist):
            return oddlist # No need for the join now
        else:
            return evenlist # No need for join.

data = input('Numbers? ')
result = iq_test(data)
print(result)

Output:

Numbers? 1 2 3 4 5
[2, 4]