On Sat, 29 Aug 2009 11:11:43 -0700, zaur wrote: > I thought that int as object will stay the same object after += but with > another integer value. My intuition said me that int object which > represent integer value should behave this way.
If it did, then you would have this behaviour: >>> n = 3 # bind the name n to the object 3 >>> saved_id = id(n) # get the id of the object >>> n += 1 # add one to the object 3 >>> assert n == 4 # confirm that it has value four >>> assert id(n) == saved_id # confirm that it is the same object >>> m = 3 # bind the name m to the object 3 >>> print m + 1 # but object 3 has been modified 5 This would be pretty disturbing behaviour, and anything but intuitive. Fortunately, Python avoids this behaviour by making ints immutable. You can't change the object 3 to have any other value, it will always have value three, and consequently n+=1 assigns a new object to n. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
