De-tupleizing a list

Tue Apr 26 15:39:32 EDT 2011

Some interesting performance comparisons, under Python 3.2. Times are relative, and are for an initial list of tuples with 500,000 items. 
(1) ans = [] #relative time: 298
 for item in lst:
 ans += list(item)
 return ans
(2) return [item[0] for item in lst] #relative time: 106
(3) from operator import itemgetter #relative time: 84
 return list(map(itemgetter(0), lst))
(4) import itertools #relative time: 63
 return list(itertools.chain.from_iterable(lst))
(5) return [x for (x,) in lst] #relative time: 52
With the caveat that 'your mileage may vary'
Regards,
Mark