Iterators in Python

iterators.py

items = [1, 2, 3]
it = iter(items)

# prints 1
print it.next()

# prints 2
print it.next()

# prints 3
print it.next()

# raise StopIteration

print it.next()

# Iteration Protocol
# 
#  An inside look at the for statement
# for x in obj:
#     # statements
#
# Underneath the covers
# _iter = iter(obj)             # Get iterator object
# while 1:
#     try:
#         x = _iter.next()      # Get next item
#     except StopIteration:     # No more items
#         break
#     # statements
#
# Any object that supports iter() and next() is  said to be "iterable".

# pending -- http://www.dabeaz.com/generators/