High memory usage - program mistake or Python feature?

[Ben S]

Aahz wrote:
> The part about high-bit characters is a complete red herring.  Note
> that you've got the file in memory twice: once from readlines() and
> once from map().  Although the readlines() call only delivers a
> temporary object, the memory consumed doesn't get returned to the OS.

Why not? Does Python keep it around in a pool, in case I ask for it
again? And is this customizable at all?

--
Ben Sizer
http://pages.eidosnet.co.uk/kylotan