CODEWITHSUNDEEP
pythonpython-2.7
Jonathan Levy
Jonathan Levy

Reputation: 57

A function to list all divisors of an integer

I'm practicing the basics of Python and I had a exercise of doing a function that asks for the user for a number and the function will return him all the divisors of that number so I done this

def divisor_generator():
    integer = raw_input("Enter a number:")
    integer = int(integer)
    list = []
    for divisors in range(integer+1):
        if divisors%integer == 0:
            list.append(divisors)
    print list

and for example the output for the integer 50 was

[50, 0]

I really want to keep it simple and I don't understand what is not good about it, I searched for so many answers but none of them was on my level of understanding. Why is my function not working as expected?

Upvotes: 1

Views: 911

Answers (3)

Sheldore
Sheldore

Reputation: 39072

Here is the correct version (I am using python 3.6.1). You need to switch the position of integer and divisors. And you need to start your range from 1 otherwise you get division by zero error

def divisor_generator():
    integer = input("Enter a number:")
    integer = int(integer)
    list = []
    for divisors in range(1, integer+1):
        if integer%divisors == 0:
            list.append(divisors)
    print (list)

By the way, in case you are also interested in a bit concise and different solution to your problem, here is another solution (you don't need it though necessarily):

integer = int(input("Enter a number:"))
divisors = [i for i in range(1, integer+1) if integer%i == 0]
print (divisors)

Upvotes: 1

Zachary Drescher
Zachary Drescher

Reputation: 56

Your modulo is backwards.

Your example is evaluating to i % 50 when you want 50 % i.

Upvotes: 1

Carcigenicate
Carcigenicate

Reputation: 45826

Your division is backwards.

I think you meant:

# I took the s off of "divisors" since it's actually a single number
integer % divisor == 0

Think of it this way, if integer is 50, and divisor is 2, with the way you had it, it would be:

2 % 50 == 0

If numerator is less than the denominator, that check will never be true, except for the when the numbers are the same. I always walk myself through this mental check just to make sure I didn't accidentally put the numbers backwards.

And, as mentioned in the comments, don't create variables called list. list is a built in function, and shadowing it has the potential to cause errors later.

Upvotes: 2

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