[Zope-dev] Re: hasattr implementation for Zope?

[Paul Winkler]

On Fri, May 27, 2005 at 01:49:00PM -0400, Tim Peters wrote:
> Nope, it's a "cell" reference to an enclosing scope, and gets looked
> up at cell-dereference speed.  In my experience, that's generally a
> bit slower than accessing a module global.  That may have to do with a
> quirk of MSVC's code generation; unsure.

Wow. If so, gcc apparently shares the same quirk.
With python 2.3.5 on my ancient gentoo box,
I get this (after substituting time.time for time.clock):

lookup1  1.55095
lookup2  1.57738
lookup3  1.4966

This is so suprising to me that I went ahead and tried
a couple of variations that I figured *must* be slower:

def lookup4(arg):
    # Doesn't get much simpler than this. 
    return object()

class C:
   
    # ok this one is pretty silly
 
    _marker = object()

    def lookup5(self, arg):
        return self._marker

lookup5 = C().lookup5

lookup1  1.53485
lookup2  1.57811
lookup3  1.47942
lookup4  2.33403
lookup5  2.0232

measurement-never-agrees-with-anyone-except-when-you-wish-it-didn't-ly y'rs,
 - Paul

-- 

Paul Winkler
http://www.slinkp.com