On Jun 7, 2:42 pm, "Daniel Fetchinson" <[EMAIL PROTECTED]>
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.
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