On Sun, Mar 8, 2009 at 10:23 PM, John Machin <sjmac...@lexicon.net> wrote:
> On Mar 9, 3:15 pm, Jack Steven <a...@hotmail.com> wrote:
>> Isn't string.Template suppose to be faster than calling replace multiple
>> times? That's what I thought until I benchmarked this code, where
>> string.Template ended up being 4 times slower.
>>
>> This doesn't make sense to me, since unlike when you are calling replace
>> multiple times, code behind Template can scan the string only once, and it
>> doesn't have to allocate multiple strings. So why is slower? Is there a way
>> to improve it's speed?
>>
>> from string import Template
>> from time import time
>>
>> def test1(format, user, channel, message):
>> nick, id, host = user
>> s = format
>> s = s.replace('$nick', nick)
>> s = s.replace('$id', id)
>> s = s.replace('$host', host)
>> s = s.replace('$channel', channel)
>> s = s.replace('$message', message)
>>
>> def test2(format, user, channel, message):
>> nick, id, host = user
>> s = Template(format)
>> d = {
>> 'nick': nick,
>> 'id': id,
>> 'host': host,
>> 'channel': channel,
>> 'message': message,
>> }
>> s = s.substitute(d)
>>
>> user = ('jacks-', 'id', '127.0.0.1')
>> channel = '#test'
>> message = 'this is a message'
>> format = '<$n...@$host> $message'
>>
>> for test in (test1, test2):
>> start = time()
>> for i in xrange(100000):
>> test(format, user, channel, message)
>> end = time()
>> print 'Done in %f seconds' % (end - start)
>
> A couple of points:
> (a) string.Template is written in Python, not C so (1) it runs slower
> (2) you can get some of your answer from the source on your computer
> (b) It has to be smarter than shotgun replaces ... You may know that
> your template contains "$nick" and not "$nick $nickname $nickers" but
> it doesn't.
IOW, the comparison being made is fatally flawed, hence the
unfavorable but incorrect results.
Cheers,
Chris
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