Looking for info on Python's memory allocation

[Steven D'Aprano]

On Tue, 11 Oct 2005 11:22:39 +0200, Lasse Vågsæther Karlsen wrote:

> This begs a different question along the same lines.

Er, no it doesn't. "Begs the question" does _not_ mean "asks the question"
or "suggests the question". It means "assumes the truth of that which
needs to be proven".

http://en.wikipedia.org/wiki/Begging_the_question
http://www.worldwidewords.org/qa/qa-beg1.htm

(Both of these sources are far more forgiving of the modern mis-usage than
I am. Obviously.)


> If I have a generator or other iterable producing a vast number of
> items, and use it like this:
> 
> s = [k for k in iterable]
> 
> if I know beforehand how many items iterable would possibly yield, would
> a construct like this be faster and "use" less memory?
> 
> s = [0] * len(iterable)
> for i in xrange(len(iterable)):
>      s[i] = iterable.next()

Faster? Maybe. Only testing can tell -- but I doubt it. But as for less
memory, look at the two situations.

In the first, you create a list of N objects.

In the second, you end up with the same list of N objects, plus an xrange
object, which may be bigger or smaller than an ordinary list of N
integers, depending on how large N is.

So it won't use *less* memory -- at best, it will use just slightly more.

Is there a way from within Python to find out how much memory a single
object uses, and how much memory Python is using in total?


-- 
Steven.