Need help porting Perl function

[eatrnr at gmail.com]

On Jun 7, 2:42 pm, "Daniel Fetchinson" <fetchin... at googlemail.com>
wrote:
> > 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.
>
> This function will take a list of integers and modify it in place such
> that it removes even integers. The removed integers are returned as a
> new list (disclaimer: I'm 100% sure it can be done better, more
> optimized, etc, etc):
>
> def mod( alist ):
>     old = alist[:]
>     ret = [ ]
>     for i in old:
>         if i % 2 == 0:
>             ret.append( alist.pop( alist.index( i ) ) )
>
>     return ret
>
> x = range(10,20)
>
> print x
> r = mod( x )
> print r
> print x
>
> HTH,
> Daniel
> --
> Psss, psss, put it down! -http://www.cafepress.com/putitdown

def mod( alist ):
    return [ alist.pop( alist.index( x ) ) for x in alist if x % 2 ==
0 ]

alist = range(10,20)
blist = mod( alist )

print alist
print blist

The same thing with list comprehensions.