[Python-Dev] PEP 309 (original) (raw)

Raymond Hettinger python at rcn.com
Sun Feb 27 01:38:59 CET 2005

I did a quick experiment:

>python -m timeit -s "from operator import itemgetter; l=range(8)" "itemgetter(1)(l)" 1000000 loops, best of 3: 0.548 usec per loop >python -m timeit -s "l=range(8)" "(lambda x:x[1])(l)" 1000000 loops, best of 3: 0.597 usec per loop That's far less of a difference than I expected from itemgetter!

You've timed how long it takes to both construct and apply the retrieval function. The relevant part is only the application:

C:\pydev>python -m timeit -r9 -s "from operator import itemgetter; s=range(8); f=itemgetter(1)" "f(s)" 1000000 loops, best of 9: 0.806 usec per loop

C:\pydev>python -m timeit -r9 -s "s=range(8); f=lambda x:x[1]" "f(s)" 100000 loops, best of 9: 1.18 usec per loop

So the savings is about 30% which is neither astronomical, nor negligible.

Raymond

More information about the Python-Dev mailing list