 <p>While Hackaholic's solution is excellent (and very functional-programming), here's an alternative using list comprehensions.</p> <p>The key ingredient is <code>zip(a,b,c)</code>, which <a href="https://docs.python.org/2/library/functions.html#zip" rel="nofollow">returns a sequence of tuples containing the ith elements of a, b, c</a>. As Joran Beasley mentions, your code will work just by adding <code>zip</code>:</p> <pre><code>d = [] for i,j,k in zip(a,b,c): d.append(i+j+k) </code></pre> <p>From here it's pretty easy to get to the list comprehension version:</p> <pre><code>d = [i+j+k for i,j,k in zip(a,b,c)] </code></pre> <p>And in fact you don't even need to unpack the tuple as <code>i, j, k</code>, instead you can sum the tuple directly:</p> <pre><code>d = [sum(tup) for tup in zip(a,b,c)] </code></pre>