title: In python individual multiplication of list values with a loop?
body: <p>If I have a list <code>data_x = [1,2,3,4]</code>, how do I multiply each element of <code>data_x</code> with each element of another list <code>data_y = [2,3,4,5]</code> and sum the values?</p>
  
  <p>The answer should be <code>1*2 +2*3 +3*4+ 4*5 = 40</code>. I am looking for some kind of <code>for</code> loop.</p>