Data structures organize and group data by type. The basic Python data structures are lists, sets, tuples, and dictionaries. Each has unique properties. Stacks implemented using lists follow first-in, last-out ordering and are useful for expressions, parentheses checking, and more. Lists allow accessing, inserting, and removing elements and are commonly used to represent stacks in Python code.

1. Data structures are “containers” that organize and group data according to type. The data structures differ
based on mutability and order.
The basic Python data structures in Python include list, set, tuples, and dictionary.
Each of the data structures is unique in its own way.

2. Stacks in Python will be made using
lists as per CBSE syllabus
List
It is a collections of items and each item has its own index value.
Index of first item is 0 and the last item is n-1.Here n is number of items in a list.
list1 = ['English', 'Hindi', 2022, 2021];
list2 = [23, 20, 32, 49, 52 ];
Indexing of list
0 1 2 3
['English', 'Hindi', 2022, 2021]
-5 -4 -3 -2 -1 Negative indexing
[23, 20, 32, 49, 52]
Positive
indexing

3. Accessing Elements of a list
Consider a list
list3 = ["sub1", "sub2", "sub3", "sub4"];
list3 = ["sub1", "sub2", "sub3", "sub4"];
print("n using positive indexing" )
print(list3[0],"n")
print(list3[1],"n")
print(list3[2],"n")
print("n using negative indexing" )
print(list3[-1],"n")
print(list3[-2],"n")
print(list3[-3],"n")
Output

4. Accessing elements of a list using loop
list3 = ["sub1", "sub2", "sub3", "sub4"];
for i in range(0, len(list3)):
print(list3[i])
In the above code range method is going from 0 to length-1 of the list.
So if length is 4 then range is going from 0 to 3
For list operations we can access elements from any index.
We can access from any direction

5. A stack is a linear data structure in which all the insertion
and deletion of data or you can say its values are done at
one end only, rather than in the middle.
That one position is
Now let us understand How to implement stack in Python using Lists

6. Applications of Stack
• Expression Evaluation: It is used to evaluate prefix, postfix and infix
expressions.
• Expression Conversion: It can be used to convert one form of
expression(prefix,postfix or infix) to one another.
• Parenthesis Checking: Stack is used to check the proper opening and
closing of parenthesis.
• String Reversal: It can be used to reverse a string.
• Function Call: Stack is used to keep information about the active functions
or subroutines.

7. Using List as Stack in Python
The concept of Stack implementation is easy in Python , because it
support inbuilt functions (append() and pop()) for stack
implementation.
By Using these functions make the code short and simple for stack
implementation.
To add an item to the top of the list, i.e., to push an item, we use
append() function and to pop out an element we use pop() function.
These functions work quiet efficiently and fast in end operations.

9. Stack interactive
program

10. Menu driven code for
stack operation