a.m1 returns a bound method which gets freed before you try checking a.m2, which ends up getting the same peice of memory. If you save a reference to the bound methods, they are forced to have separate objects.
>>> class A: ... def m1(self): print "m1" ... def m2(self): print "m2" ... >>> a = A() >>> a.m1() m1 >>> a.m2() m2 >>> id(a.m1) 25402184 >>> id(a.m2) 25402184 >>> b = a.m1 >>> c = a.m2 >>> id(b) 25402184 >>> id(c) 25541848 -Chris On Thu, Dec 15, 2005 at 02:19:15PM -0700, Stuart McGraw wrote: > The following was cut and pasted exactly (except for the > # lines which I added after the fact) from an interactive python > session in a Window 2000 cmd.exe window. > > Can somebody please explain to me what the heck is > going on?!?! > > Python 2.4.2 (#67, Sep 28 2005, 12:41:11) [MSC v.1310 32 bit (Intel)] on win32 > Type "help", "copyright", "credits" or "license" for more information. > >>> class A: > ... def m1(self): print "m1" > ... def m2(self): print "m2" > ... > >>> a = A() > >>> a.m1() > m1 > >>> a.m2() > m2 > # ok, both methods work and give the expected results > # so i presume they are different methods. > >>> id(a.m1) > 9202984 > >>> id(a.m2) > 9202984 > >>> id(a.m1)==id(a.m2) > True > # Huh? They seem to be the same. > >>> a.m1 is a.m2 > False > # But not the same... > >>> a.m1 > <bound method A.m1 of <__main__.A instance at 0x00923B98>> > >>> a.m2 > <bound method A.m2 of <__main__.A instance at 0x00923B98>> > # Let's look at them in hex... > >>> hex(id(a.m1)) > '0x8c6d28' > >>> hex(id(a.m2)) > '0x8e7b48' > # Now they are different. 0x8c6d28->9202984, 0x8e7b48->9337672 > >>> id(a.m1) > 9337672 > >>> id(a.m2) > 9337672 > # Now they are both equal to the second one. > >>> hex(id(a.m1)) > '0x8e7b48' > >>> hex(id(a.m2)) > '0x8e7b48' > # in hex too. > >>> id > <built-in function id> > >>> hex > <built-in function hex> > # just double checking! > > Why??? This is so bizarre I'm sure I am doing something > really stupid. > > > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
