"""
Example (and doctest):
>>> for n, islast in iter_islast(range(4)):
... if islast:
... print "last but not least:",
... print n
...
0
1
2
last but not least: 3
>>> list(iter_islast(''))
[]
>>> list(iter_islast('1'))
[('1', True)]
>>> list(iter_islast('12'))
[('1', False), ('2', True)]
>>> list(iter_islast('123'))
[('1', False), ('2', False), ('3', True)]
>>>
"""
def iter_islast(iterable):
""" iter_islast(iterable) -> generates (item, islast) pairs
Generates pairs where the first element is an item from the iterable
source and the second element is a boolean flag indicating if it is the
last item in the sequence.
"""
it = iter(iterable)
prev = it.next()
for item in it:
yield prev, False
prev = item
yield prev, True
