[Diez B. Roggisch]
> > out:) But I wanted a general purpose based solution to be available that
> > doesn't count on len() working on an arbitrary iterable.
[Peter Otten]
> You show signs of a severe case of morbus itertools.
> I, too, am affected and have not yet fully recovered...
Maybe you guys were secretly yearning for a magical last element
detector used like this:
for islast, value in lastdetecter([1,2,3]):
if islast:
print 'Last', value
else:
print value
Perhaps it could be written plainly using generators:
def lastdetecter(iterable):
it = iter(iterable)
value = it.next()
for nextvalue in it:
yield (False, value)
value = nextvalue
yield (True, value)
Or for those affected by "morbus itertools", a more arcane incantation
would be preferred:
from itertools import tee, chain, izip, imap
from operator import itemgetter
def lastdetecter(iterable):
"fast iterator algebra"
lookahead, t = tee(iterable)
lookahead.next()
t = iter(t)
return chain(izip(repeat(False), imap(itemgetter(1),
izip(lookahead, t))), izip(repeat(True),t))
Raymond
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