Question

The following code works just fine. But it seems so verbose, surely there is a more elegant way to calculate this?

The idea is that I have a list of 100 incrementing timestamps, I want to look at those timestamps and calculate the mean time between each time-stamp.

The code below functions, but I’m sure it’s really inefficient to be reversing lists like this.

Any suggestions?

#!/usr/bin/python 

nums = [1,4,6,10]
print nums
nums_orig = list(nums)

nums_orig.pop()
nums.reverse()
nums.pop()
nums.reverse()

print nums
print nums_orig

total = 0

for idx, val in enumerate(nums):
  difference = val - nums_orig[idx]
  total += difference
  print idx, val - nums_orig[idx]

print "Mean difference is %d" % (total / len(nums))

Answer 1

What you are looking for is

>>> nums = [1,4,6,10]
>>> [x-y for x,y in zip(nums[1:],nums)]
[3, 2, 4]
>>> delta=[x-y for x,y in zip(nums[1:],nums)]
>>> float(sum(delta))/len(delta)
3.0

Solution with using Starmap

>>> from itertools import starmap
>>> from operator import sub
>>> sum(starmap(sub,zip(nums[1:],nums)))/float(len(nums)-1)
3.0