Python Iterator Iterbale

################################################
## Writing own iterators
## Two ways:
##    1) using __iter__ and __next__ for Python 3.0
##       using __iter__ and next() for Python 2.7      
##    2) using generator functions
##    3) They can go only forward, no backwards
################################################

class IterClass:
def __init__(self, listA):
self.index = 0
self.elments = listA
def __iter__(self): #To make an object sequence
return self
def next(self): #in 2.7 use next(), in 3.0 use __next__()
if self.index >= len(self.elments):
raise StopIteration
index = self.index
self.index += 1
return self.elments[index]

ic = IterClass(['A','B','C'])
for each in ic:
print each
print '------'
ic = IterClass(['A','B','C'])
print(next(ic))
print(next(ic))
print(next(ic))
#print(next(ic)) #This raoses StopIteration
print'-------'

ll = range(0,5)
print ll

#List object is iterable but not iterator
print dir(ll) #it has __iter__ only, but no next/__next__ method
#next(ll) will fail

ll_iter = ll.__iter__()
print dir(ll_iter) #it has next/__next__ method


print ll_iter
print dir(ll_iter)
print next(ll_iter)
print next(ll_iter)
print next(ll_iter)
print next(ll_iter)
print next(ll_iter)
#print next(ll_iter) #It will throw StopIteration

print '###########'
ll_iter = ll.__iter__()

while True:
try:
item = next(ll_iter)
print item
#except StopIteration:
# print e
# break
except Exception,e:
break

print '$$$$$$$$$$$$'
ll_iter = ll.__iter__()
for each in ll_iter:
print each

Output:
A
B
C
------
A
B
C
-------
[0, 1, 2, 3, 4]
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__delslice__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getslice__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__setslice__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']
['__class__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__iter__', '__length_hint__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'next']
<listiterator object at 0x03978190>
['__class__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__iter__', '__length_hint__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'next']
0
1
2
3
4
###########
0
1
2
3
4
$$$$$$$$$$$$
0
1
2
3

4