title: Is there a way to subtract an element with next element in a python list?
body: <p>Iam new to programming and started learning python.
  Iam having a list if numbers
  a = [1,2,3,4,5]
  Logic should be 1-2-3-4-5 to get the result as -13.
  Someone help me with the python code for this problem.</p>