Needing help creating a function-CodePudding

I';m a bit confused right now as to what I'm supposed to be doing.

CodePudding user response：

That happens because you're trying to slice an integer, not a list.

You can solve this problem by changing the integer to a list, and then try using slicing.
This can be done by the code below.

listNum = list(map(int, str(num)))

use this listNum instead of n in your code.

CodePudding user response：

You need to repeat the process until the result is a single digit.

Then, the number is divisible by 11 if and only if that single digit is 0.

For example:

def div_11(n):
    while n > 9:
        s = str(n)
        x = sum([int(s[i]) for i in range(0,len(s),2)]) # sum of digits in even places
        y = sum([int(s[i]) for i in range(1,len(s),2)]) # sum of digits in odd places
        n = abs(x - y) # just in case the intermediate result is negative
    return n == 0

CodePudding user response：

You are passing an integer to the function, which can't be sliced. The passed number should be a string in order to pick the alternative digits using slicing.

Furthermore, you're still using the modulus operator to determine the divisibility by 11, which can be replaced by a look-up inside a list.

Try the following:

def div_11(n):
    n = str(n)
    alternative = sum(int(digit) for digit in n[::2]) 
    second_alternative = sum(int(digit) for digit in n[1::2])

    if (alternative - second_alternative) in [-11, 0, 11]:
        return True
    else:
        return False