Packages and Datastructures - Python

1. PACKAGES &
DATASTRUCTURES in
PYTHON
1
By
B.Hemalatha
Assistant Professor
VEC

2. PACKAGES / LIBRARY
 In Computer we store files in organized hierarchies
 Subdirectories
 Files
 Large projects in Python are organized as Packages
which consists of many
 Sub-Packages
 Similar Modules
 Packages makes projects easy to manage and conceptually clear
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3. PACKAGES / LIBRARY
 Python package is a directory containing
 Sub-packages
 Modules
 Along with an __init__.py file
Python module
 Is a . py file
 Contains functions, variables
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double underscore

4. Mensuration
Square.py
Rectangle.py
Circle.py
Eg 1. PACKAGE
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M
O
D
U
L
E
S
Directory
Package

5. • Game Development Package Organization
Eg 2.PACKAGES / LIBRARY
5
PACKAGE
list
SUBPACKAGES
M
O
D
U
L
E
S

6. • Steps to create a package
– Create a directory with the package name
– Create modules under it
– Create a file __init__.py in the directory
Note : File __init__.py is a simple file required to make python treat the
directory on the disk as packages of python
• Access packages and its modules
– from PACKAGE_NAME import MODULE_NAME
• Access functions in modules
– Use dot operator “ . ”
– MODULE_NAME . FUNCTION_NAME
PACKAGES / LIBRARY
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7. PACKAGES / LIBRARY
mensuration
square.py rectangle.py
Modules/
Python Files
Directory /
Package
Example:
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8. Step1 : Folder/Directory Creation:
Folder/directory named “mensuration”
creation
Step 2: Module Creation - I: “square.py”
# Square Module
def area(side):
return side * side
def peri(side):
return 4 * side
PACKAGES / LIBRARY
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9. Step 2 : Module Creation - II: “ rectangle.py”
# Rectangle Module
def area(length,breadth):
return length*breadth
def peri(length,breadth):
return 2*(length+breadth)
Step 3 : file __init__.py Creation
PACKAGES / LIBRARY
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10. To Access Packages and its Modules
from mensuration import square,rectangle
To Access functions inside the Modules
square . area (side)
rectangle . area (length,breadth)
PACKAGES / LIBRARY
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#Rectangle Module
def area(length,breadth):
def peri(length,breadth):
# Square Module
def area(side):
def peri(side):

11. 1. Package in Python is a
– (a) File
– (b) Database
– (c) hierarchical file directory
– (d) hierarchical database directory
»(Ans: c)
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12. 2. To include a package in python we use
– (a) include statement
– (b) import statement
– (c) package include statement
– (d) package import statement
»(Ans: b)
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13. 3. A Package contains
– (a) sub-packages
– (b) modules
– (c)__init__.py
– (d) All the above
»(Ans: d)
4. Python supports built in packages
– (a) Yes
– (b) No
»(Ans: a)
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14. 5. The package folder contains a special file
called__________
– (a) __init__.py,
– (b) Pack_.py
– (c)_pack_,py
– (d)_init_pack_.py
»(Ans: a)
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15. INTRODUCTION TO
DATA STRUCTURES
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16. Data structure
 way to store and organize data
 helps in writing efficient programs in any
language
Python is a high-level, interpreted, interactive
and object-oriented scripting language using
which we can study the fundamentals of data
structure in a simpler way as compared to
other programming languages.
Data structure in Python
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17. Data structure in Python
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Data Structures in Python
Built-in Data Structures User-Defined Data Structures
List
Tuple
Dictionary
Set
Stack
Queue
Tree
Graph
Linked
list

18. Today we will focus on few Data Structures
1.Stacks
2.Queues
3.Graph
Data structure in Python
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19. Stack
Data structure - Stack
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20. Stack
 is an ordered collection of items
 addition of new items
 removal of existing items
 this ordering principle is called Last-In First-Out(LIFO)
A Stack of Books A Stack of Primitive Python Objects
Data structure - Stack
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always takes place at the same end
usually top

21. Data structure - Stack
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Stack
Insertion
“PUSH”
Deletion
“POP”
Top
LIFO PRINCIPLE

22. Stack using LIST in Python
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Stack LIFO PRINCIPLE

23. Stack using LIST in Python
Example:
# empty stack
stack = [ ]
# push operation # pop operation
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OUTPUT
stack.append(10) stack =[10]
stack.append(20) stack =[10,20]
stack.append(30) stack =[10,20,30]
OUTPUT
stack.pop() stack =[10,20,30]
stack.pop() stack =[10,20]
top
top
top
top
top

24. Data structure - Queue
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QUEUE

25. Queue
 is an ordered collection of items
 Addition of new items happens at one end, called the “rear,”
 Removal of existing items occurs at the other end, called the “front.”
 This ordering principle is sometimes called First-In First-Out (FIFO)
A Queue of Python Data Objects
Data structure - Queue
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26. Insertion – Enqueue
Deletion - Dequeue
Data structure - Queue
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QUEUE
Rear Front
FIFO PRINCIPLE

27. Queue using LIST in Python
Example:
# empty queue
queue = [ ]
# enqueue operation # dequeue operation
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OUTPUT
queue.append(10) queue =[10]
queue.append(20) queue =[10,20]
queue.append(30) queue =[10,20,30]
OUTPUT
queue.pop(0) queue =[10,20,30]
queue.pop(0) queue =[20,30]
rear
rear
front
front
rear

28. QUEUE APPLICATIONS – SHARING PRINTER RESOURCE
Data structure - Queue
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A
B
C
D
Job 1 Job 2
Job 3
Job 3 Job 2 Job 1
Printer queue
front

29. Data structure - Graph
Graph
Data is stored in a collection of vertices(nodes)
interconnected by edges (path)
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30. Graph using DICTIONARY
Example:
# GRAPH structure
graph = { “a”:[“d”], “b”:[“c”],“c”:[“d”,”e”],
“d”: [“a”,”c”] ,”e”:[“c”]}
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31. Application –
Undirected Graph
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• Social Network – FACEBOOK
Suggest Friends

32. Application – Directed Graph
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• World Wide Web

33. 1. Consider the following operation performed on a stack
Push(1);
Pop();
Push(2);
Push(3);
Pop();
Push(4);
Pop();
After the completion of all operation, the number of elements
present in stack are
- (a) 1
- (b) 2
- (c) 3
- (d) 4
»(Ans: a)
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34. 2. A list of elements in which deletion can be
done from one end (front) and insertion can
take place only at the other end (rear) is known
as
- (a) Queue
- (b) Stack
- (c) Tree
- (d) Linked list
»(Ans: a)
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35. 3. Google Map is an application of
- (a) Tree
- (b) Stack
- (c) Graph
- (d) Queue
»(Ans: c)
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36. Thank you
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