I need to test whether each number from 1 to 1000 is a multiple of 3 or a multiple of 5. The way I thought I'd do this would be to divide the number by 3, and if the result is an integer then it would be a multiple of 3. Same with 5.
How do I test whether the number is an integer?
here is my current code:
n = 0
s = 0
while (n < 1001):
x = n/3
if isinstance(x, (int, long)):
print 'Multiple of 3!'
s = s + n
if False:
y = n/5
if isinstance(y, (int, long)):
s = s + n
print 'Number: '
print n
print 'Sum:'
print s
n = n + 1
You do this using the modulus operator, %
n % k == 0
evaluates true if and only if n
is an exact multiple of k
. In elementary maths this is known as the remainder from a division.
In your current approach you perform a division and the result will be either
It's just the wrong way to go about testing divisibility.