[Nick Coghlan]
> So, using "".join is roughly three times as fast as abusing sum :)
True in the case where you're concatenating three strings, but what
about 100 strings?
(Full source attached)
Py> timeit.Timer("sum(strings, ai)", setup).repeat()
[33.553668413164239, 32.861660909417253, 33.092705357803851]
Py> timeit.Timer("''.join(strings)", setup).repeat()
[5.4385152302876492, 5.3633637794747671, 5.3587657090496066]
Py> timeit.Timer(" + ".join('"' + s + '"' for s in strings), "").repeat()
[17.726616371633828, 17.785511845779279, 18.179861127601413]
So at 100 strings, the difference is over 5x, and I assume you'll see
the relative distance increase as you increase the number of strings.
Timothy Fitz
import timeit
from random import choice
from random import randrange
from string import uppercase
setup = """
class additive_identity(object):
def __add__(self, other):
return other
ai = additive_identity()
from random import choice
from random import randrange
from string import uppercase
strings = ["".join(choice(uppercase) for i in range(randrange(10))) for i in
range(100)]"""
strings = ["".join(choice(uppercase) for i in range(randrange(10))) for i in
range(100)]
print "SUM:", timeit.Timer("sum(strings, ai)", setup).repeat()
print "JOIN:", timeit.Timer("''.join(strings)", setup).repeat()
print "ADD:", timeit.Timer(" + ".join('"' + s + '"' for s in strings),
"").repeat()_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
