LIST OPERATIONS
===============
Traversing on List data:
========================
moving on the list element by element ==> traversing

ex: [1,2,3,4,5,6]
==> all odd elements with list ==> [1,3,5]

for traversing:
	1) using while loop
	2) using for loop

1) using while loop:
====================
Syntax:
	initialization (index for start traversing)

	while index < length-list/number:
		loop body operation
		update

len():
=====
It is an inbuilt method, which we can use to find the size or length or total number of elements of the string.

Syntax:
	len(str-data)

# Traversing on List using while loop

# WAP TO PRINT ALL THE LIST ELEMENTS WITH CORRESPONDING POSITIVE AND NEGATIVE INDEX VALUE.

"""
input: "python"
Output:
    the character at positive '0' = 'p'

    the character at negative index '-1' = 'n'

    the character at positive index '0' and at negative index '-6' = 'p'
"""

# traversing with positive index values

strData = "Python"

length = len(strData)

# print("The Length of the string = ",length)

index = 0

while index < length:
    # print("The Character at positive index {} is = {}".format(index,strData[index]))
    print("The Character at {} and at {} is = {}".format(index,index-length,strData[index]))
    index = index + 1
print()

# traversing with negative index values

index = -1

while index >= -length:
    # print("The Character at negative index {} is = {}".format(index,strData[index]))
    print("The Character at {} and at {} is = {}".format(index,index + length,strData[index]))
    index = index - 1

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

# List Traversing using while loop

listData = eval(input("Enter a list:"))

length = len(listData)

index = 0

while index < length:
    print("Element of list at {} and at {} is = {}".format(index, index-length,listData[index]))
    index += 1
print()

index = -1

while index >= -length:
    print("The Element aof list at {} and at {} is = {}".format(index,index+length,listData[index]))
    index -= 1

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

2) using for loop:
==================
Syntax:
	for iter_var in range():
		block operation

	for iter-var in list-data:
		block of operation

# List Traversing using for loop

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

index = 0
length = len(listData)

# in forward access

for ele in listData:
    print("The Element at {} and at {} is = {}".format(index,index-length,ele))
    # print(ele,end = "\t")
    index += 1
print()

# in reverse access
index = -1

for ele in listData[::-1]:
    print("The Element at {} and at {} is = {}".format(index,index + length,ele))
    index -= 1

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

Math Operations on List:
========================
1) LIST CONCATENATION
======================
Joining of two or more list data's into single list.
==> symbol: +
Syntax:
	list1 + list2 + list3 + .....
 
2) LIST REPETITION
===================
To repeat the content of the list for several number of times, we can use "list Repetition".
Symbol: *
Syntax:
	list-data * n

# List Math Operations

# List Concatenation

l1 = [1,3,5,7,9]
l2 = [0,2,4,6,8]

res_list = l1 + l2

# List Repetition

list_repeat = l1 * 5

print("The Concatenated list = ",res_list)
print("Repeated List = ",list_repeat)

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

Membership Check on List:
=========================
we can use: membership operators
	in and not in

# Membership check

l1 = [1,3,5,7,9,'python','object','oriented', 'language']

print('python' in l1)   # True
print('object' not in l1)   # False
print(7 in l1)  # True
print(9 not in l1)  # False

========================================
List Comparison:
================
we can use: Relational Operators

list1 == list2 or list1 != list2
=================================
1) Check lengths of the list:
	if lengths of both lists are same, it will consider for individual element check
	if lengths of both lists are not same, equality ==> False

# Equality Check on list

l1 = [1,2,3,4,5]
l2 = [1,2,3,4,5]
l3 = [1,3,5,7,9]
l4 = [1,2,3,4]

print(l1 == l2)
print(l1 == l3)
print(l1 == l4)

print(l1 != l2)
print(l1 != l3)
print(l1 != l4)

l1 < l2 S2 | l1 <= l2 | l1 >= l2
========================================
1) return: False/True (based on the lengths)
	when lists are with different lengths
2) the comparison is defined on the list element by element, when the lengths are same

l1 = [1,2,3,4,5]
l2 = [1,2,3,4,5]
l3 = [1,3,5,7,9]
l4 = [1,2,3,4]

print(l1 < l2);print(l1 > l2)
print(l1 <= l2);print(l1 >= l2)
print(l2 < l4);print(l2 > l4)