Bart Willems wrote: > Dennis Lee Bieber wrote: >> On 14 Apr 2007 06:35:34 -0700, "jamadagni" <[EMAIL PROTECTED]> declaimed >> the following in comp.lang.python: >> In Python, the "variable" NAME does NOT define storage; unlike most >> other classical languages where the "variable name" is a storage >> address, and the value of the RHS is COPIED to that address. Python does >> not do such copying. Names are references to the RHS object itself. >> >> a = 5 >> >> means that somewhere in memory is an integer object with the value "5"; >> the name "a" is now "pasted onto" that integer object. >> >> b = a >> >> finds the object that has the name "a" stuck to it, and sticks a second >> name "b" onto the same object. There is still only one "5" in memory. > > I can try this in interactive mode: > >>> a = 5 > >>> b = a > >>> a += 1 > >>> print b > 5 > > So, if /a/ and /b/ where pointing to the *same* "5" in memory, then I > would expect b to be increased, just as a. But after increasing a, b is > still 5... > > Lists behave as described above, integers and floats don't. > > By the way, a classic language like C has features like this too; > they're called pointers.
I think that after a += 1, a memory location with a 6 is created and now a points to that because += has assignment buried in it. -- http://mail.python.org/mailman/listinfo/python-list
