title: Trying to understand the double index in python
body: <pre><code>def countSmaller(self, nums):
          def sort(enum):
              half = len(enum) / 2
              if half:
                  left, right = sort(enum[:half]), sort(enum[half:])
                  for i in range(len(enum))[::-1]:
                      if not right or left and left[-1][1] &gt; right[-1][1]:
                          smaller[left[-1][0]] += len(right)
                          enum[i] = left.pop()
                      else:
                          enum[i] = right.pop()
              return enum
          smaller = [0] * len(nums)
          sort(list(enumerate(nums)))
          return smaller
  </code></pre>
  
  <p>I am a new python coder so this query!.. In left[-1][1] , I understood [-1] makes me think the last index but what does the second index [1] mean.</p>