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Permanent objects?

Erik Max Francis max at alcyone.com
Wed Dec 25 05:21:19 EST 2002 
Armin Steinhoff wrote:

> Could someone explain in _detail_ why this happens?

As an optimization.  Since integer objects are immutable, when you ask
for an object representing, say, the number 2, it doesn't matter whether
or not that object is a physically different object from others
representing the same number, since it's immutable.  Compare that, say,
with a list object:  Since lists are mutable, it definitely does make a
difference whether any given empty list (say) is the same object as any
other empty list.

Since small integers get created a lot, it sometimes make sense to
precache the creation of those objects and simply use the same physical
object, rather than going to the expense of creating a new one (with the
overhead of the allocation of memory, etc.) each time.

-- 
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