On 08/10/2012 06:37 AM, Chris Angelico wrote: > On Fri, Aug 10, 2012 at 8:12 PM, Mok-Kong Shen > <mok-kong.s...@t-online.de> wrote: >> Thanks for the explanation of the output obtained. But this means >> nonetheless that parameters of types lists and strings are dealt with >> in "inherently" (semantically) different ways by Python, right? > It's nothing to do with parameters, but yes, lists are mutable and > strings are immutable. A tuple will behave the same way a string does: > >>>> a > (1, 2, 3, 4) >>>> b=a >>>> a+=5, # note that "5," is a one-element tuple >>>> a > (1, 2, 3, 4, 5) >>>> b > (1, 2, 3, 4) > > > By the way: > > On Fri, Aug 10, 2012 at 8:07 PM, Dave Angel <d...@davea.name> wrote: >> But if you said c=651 and d=651, you'd have two >> objects, and the two names would be bound to different objects, with >> different ids. > To be more accurate, you *may* have two different objects. It's > possible for things to be optimized (eg with small numbers, or with > constants compiled at the same time). > > ChrisA
You're right, of course. But I picked the value of 650+ deliberately, as I believe CPython doesn't currently optimize ints over 256. -- DaveA -- http://mail.python.org/mailman/listinfo/python-list
