LIST OPERATIONS
===============

LIST IS MUTABLE:
==============

ld = eval(input("Enter a list data:"))

print(id(ld))


print(ld[0])

ld[0] = 100

print(id(ld))
print(ld)

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

count()
=====
==> use to find the total number of occurrences of the specified element within the list.
Syntax:
	list_data/list_object.count(element)

==> If the specified element in count() is not the member of the list: 
	return = '0'

==> we cannot count the number of occurrences of the specified within the range.

ld = [1,2,3,4,5,1,3,5,7,9,1,2,3,4,5,1,3,5,7,9,2,4,6,8,10]

# if the specified element is the member of the list

print(ld.count(1))
print(ld.count(7))

# if the specified element is not the member of the list

print(ld.count(20))

# counting the element within the range, canot count

# print(ld.count(2,1,10))

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

index()
=====
==> use to find the first occurrence of the specified element in the given list.
Syntax:
	list_data/list_object.index(element)

==> When the specified element is not a member of the list: index() returns "Value Error".
==> index() can allow to find the element within the specified range.
Syntax:
	list_data/list_object.index(element,start,stop)

ld = [1,2,3,4,5,5,4,3,2,1,1,3,5,7,9]

# when the specified element is the member of list
# first occurrence of element is returned.

print(ld.index(9))
print(ld.index(2))

# when the specified element is not the member of list
# return: value error

# print(ld.index(100))

# finding in between range

print(ld.index(5,1,10))

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

Adding of new elements into list
========================
1) append()
=========
==> use to add any element into the list at the last/end by default.
Syntax:
	list_data/list_object.append(element)

ld = list()

print("The List before the append operation is = ")
print(ld)

ld.append(10)
ld.append(20)
ld.append(30)
ld.append(40)
ld.append(50)

print(ld)

=======================================
2) insert()
========
==> Use to add a new element at the given index position
Syntax:
	list_data/list_object.insert(index,element)
==> if the specified index is from out of range:
	the insertion of an element is at the last index automatically.

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

print(ld)

ld.append(20)

ld.insert(1,100)

# if the specified index is exceeded the index range

ld.insert(10,1000)

print(ld)

===========================================
3) extend()
========
==> to extend a list of data to another list.
ex: l1 
l2
l1 <====== l2

Syntax:
	source_list_data.extend(destination_list_data)\

ld1 = [1,2,3,4]
ld2 = [5,6,7,8]

print("ld1 = ",ld1)
print("ld2 = ",ld2)

ld1.extend(ld2)

print("ld1 = ",ld1)
print("ld2 = ",ld2)

ld2.extend(ld1)

print("ld1 = ",ld1)
print("ld2 = ",ld2)

===============================================================
Note:
====
Method/Function ==> define the functionality
functionality:
	take inputs
	process the inputs
	give an output

sum() ==> 12, 24
12 + 24
36
is count() return anything?
====================
yes,
an integer ==> count of occurrences of the specified element

is index() return anything?
====================
yes,
an integer ==> the first index value of the specified element

is append() return anything?
======================
yes,
None

ld = [1,2,3,4,5,2,2]

x = ld.count(2) # 1
print(x)

y = ld.index(2)
print(y)

z = ld.append(100)
print(z)

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

Removal of elements from list
=======================
1) remove()
=========
==> use to remove the specified element only from the given list.
Syntax:
	list_data/list_object.remove(element)
==> if the specified element is unknown to the given list:
	remove() return: Value Error.

ld = [1,2,3,4,5,6,7,8,9,10]

print(ld)

print(ld.remove(3))
# ld.remove(5,6)

# if the specified element is not the member of a lis ==> Value Error
# ld.remove(100)

print(ld)

================================================
2) pop()
======
==> use to remove the last element from the given list automatically.
Syntax:
	list_data.pop()

==> we can use pop() to remove the specified element based on the index.
Syntax:
	list_data.pop(index)

ld = [1,2,3,4,5]

print(ld)

# ld.pop()
# ld.pop()

ld.pop(1)

print(ld)

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

del
===
==> del is an attribute/property
	use to delete any data permanenlty.
Syntax:
	del value_name
==> using del property, we can delete any element from the list based on the index
==> even we can also delete the entire list also permanently.

a = 100
b = 200
l1 = [10,20,30,40,50]

print(a,b)

del a

print(l1)

del l1[2]

# print(a,b)
print(l1)

del l1

# print(l1)