title: Using python, how can I merge or join two lists so that their values don't overlap?
body: <p>First off, I apologize for my inaccurate vocabulary. I am an absolute ground-zero beginner. Anyways, I am attempting to solve this problem: 
  <a href="http://projecteuler.net/problem=1" rel="nofollow">http://projecteuler.net/problem=1</a></p>
  
  <p>To be brief, I'm trying to write a script that will find the sum of all the multiples of 3 or 5 below 1000.</p>
  
  <p>My (extremely basic) approach was with this program:</p>
  
  <pre><code>##Multiples of 3
  x = range(3, 1000, 3)
  
  ##Multiples of 5
  y = range(5, 1000, 5)
  
  a = sum(x)
  b = sum(y)
  n = a + b
  
  print n
  </code></pre>
  
  <p>I realized that this was wrong because there are numbers like 15 that are included twice (it's a multiple of both 5 and 3).
  So is there a way to fix this or am I approaching this problem from a completely wrong angle?
  Or do I need to just study more before I try solving this problem?
  I also apologize if this has been explained in a previous post, but I looked around for a bit. </p>