Python 2.6+ and 3.* have next(), but pre-2.6 only offers the object.next method. Is there a way to get the next() style in pre-2.6; some "def next():" construction perhaps?
class Throw(object): pass
throw = Throw() # easy sentinel hack
def next(iterator, default=throw):
"""next(iterator[, default])
Return the next item from the iterator. If default is given
and the iterator is exhausted, it is returned instead of
raising StopIteration.
"""
try:
iternext = iterator.next.__call__
# this way an AttributeError while executing next() isn't hidden
# (2.6 does this too)
except AttributeError:
raise TypeError("%s object is not an iterator" % type(iterator).__name__)
try:
return iternext()
except StopIteration:
if default is throw:
raise
return default
(throw = object()
works too, but this generates better docs when inspecting, e.g. help(next)
. None
is not suitable, because you must treat next(it)
and next(it, None)
differently.)