easy question on parsing python: "is not None"

[Gabriel Genellina]

En Mon, 09 Aug 2010 08:41:23 -0300, saeed.gnu <saeed.gnu at gmail.com>  
escribió:

> "x is y"          means   "id(y) == id(y)"
> "x is not y"      means   "id(x) != id(x)"

No; consider this:


py> id([])==id([])
True
py> [] is []
False

Comparing id's is the same as using the is operator only if you can  
guarantee that both operands are alive at the same time.


-- 
Gabriel Genellina