Home Original page

Splitting lists

Terry Reedy tjreedy at udel.edu
Thu Feb 27 17:16:21 EST 2003 
"Létezõ" <letezo at fw.hu> wrote in message
news:mailman.1046363056.19603.python-list at python.org...
> Dear List Splitters!
>
> Thanks to Steven for the performance analysis and Alex & Duncan for
the
> their more impressive solutions. It would be interesting to insert
the new
> "impressive" solutions into the performace test loop. Which is the
fastest?
>
> Proposed solutions in reverse time order:

Here is another 'symmetrical' version

tl,fl = [],[]
ta,fa = tl.append, fl.append
for i in range(-5,5): ((i >=0) or fa(i)) and ta(i)

fl,tl
#([-5, -4, -3, -2, -1], [0, 1, 2, 3, 4])

but unless it surprised me by being faster, I also prefer

> # Duncan: (my current favourite)
> fl=[]
> tl = [ x for x in test if fn(x) or fl.append(x) ]

with fl.append factored out

Terry J. Reedy
More information about the Python-list mailing list