Need help porting Perl function

[kj]

Hi.  I'd like to port a Perl function that does something I don't
know how to do in Python.  (In fact, it may even be something that
is distinctly un-Pythonic!)

The original Perl function takes a reference to an array, removes
from this array all the elements that satisfy a particular criterion,
and returns the list consisting of the removed elements.  Hence
this function returns a value *and* has a major side effect, namely
the target array of the original argument will be modified (this
is the part I suspect may be un-Pythonic).

Can a Python function achieve the same effect?  If not, how would
one code a similar functionality in Python?  Basically the problem
is to split one list into two according to some criterion.

TIA!

Kynn
 
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