On 2013-08-10 21:03, Krishnan Shankar wrote: > >>> a=10 > >>> id(a) > 21665504 > >>> b=a > >>> id(b) > 21665504 > >>> c=10 > >>> id(c) > 21665504 > > I am actually assigning new value to c. But from the value of id() > all three variables take same location. With variables a and b it > is ok. But why c taking the same location?
As an internal optimization, CPython caches small integer values >>> a = 256 >>> b = 256 >>> a is b True >>> a = 257 >>> b = 257 >>> a is b False Because it's an internal implementation detail, you shouldn't count on this behavior (Jython or Cython or IronPython may differ; or future versions of Python may cache a different range of numbers). Generally, if you are using the "is" operator to compare against anything other than None, you're doing it wrong. There are exceptions to this, but it takes knowing the particulars. -tkc -- http://mail.python.org/mailman/listinfo/python-list
