ld = [1,3,5,7,9]

for l in ld:
    print(l)

# iterable can make the traversing on the collection like list, tuple, set etc, element by element

# Iterable can return only one element/value at a time.
print()

i = 0
while i < len(ld):
    print(ld[i])
    i+=1

ITERATOR:
=========
==> Iterator is an object
	which can enable the traversing on the collection like: list, tuple, dictionary etc.
==> Iterator Object, can return only one element at a item.
==> can also return the stream of data.
==> two methods:
	iter() ==> can return the iterator object to iterate over the data
	next() ==> can return the next element in the collection.

d1 = iter("Hello")
d2 = iter([1,3,5,7,9])

print(d1)
print(d2)

print(d1.__next__())
print(d1.__next__())
print(d1.__next__())
print(d1.__next__())
print(d1.__next__())
======================================

Iterable Vs Iterator:
=====================
Iterable can return only one element at a time.
Iterable cannot use the memory efficiently.

Iterator can return the stream of data at a time.
Iterator can use the memory efficiently.

data = iter(range(5))

print(data)

print(data.__next__())
print(data.__next__())
print(data.__next__())
print(data.__next__())
print(data.__next__())
print(data.__next__())

===================================================
# d = 100

# for i in d:
#     print(i)

# Iterable like: while, for cannot iterate on the integer (primitive data)object.

d = iter(100)

print(d)

# Like iterable, iterator can also not iterate on the primitive data object.

=================================================
StopIteration:
==============
==> an exception
	can be occurred when the number of iterations exceeded over the collection.

Handling the "StopIteration" Exception:
========================================

d = iter((1,3,5,7,9))

print(d)

while True:
    try:
        n = next(d)
        print(n)
    except StopIteration:
        break

=======================================

for i in range(1,10,2):
	print(i)	# 1 3 5 7 9


# WAP TO GENERATE ODD NUMBERS FROM THE GIVEN RANGE USING ITERATOR.

class OddNumberGeneration:
    def __init__(self,last):
        self.start = -1
        self.last = last

    def __iter__(self):
        return self

    def __next__(self):
        if self.start < self.last - 1:
            self.start += 2 # self.start = self.start + 2 # -1 + 2 = 1 3 5 7
            return self.start
        else:
            raise StopIteration

obj = OddNumberGeneration(10)
while True:
    try:
        x = next(obj)
        print(x)
    except StopIteration:
        break