Python programming lab programs Python Python Python Python Python PythonPython Python Python Python Python Python Python Python Python Python Python Python Python Python Python Python Python Python

1. PYTHON PROGRAMMING

2. WHAT IS PYTHON??
 Python is a General Purpose object-oriented
programming language, which means that it can
model real-world entities.
 The distinctive feature of Python is that it is
an interpreted language.
 The Python IDLE (Integrated Development
Environment) executes instructions one line at a
time.

3. PYTHON FEATURES

4. -STRINGS ARE IMMUTABLE
Code Comment Result
print str # prints complete string Hello, World!
print str[0] # prints first character of the string H
print str[-1] #prints last character of the string !
print str[1:5] # prints character starting from index 1 to 4
# prints str[start_at : end_at-1]
ello
print str[2:] #prints string starting at index 2 till end of the llo, World!
print str * 2 # asterisk (*) -is the repetition operator. Prints
string two times.
Hello,
Hello, World!
print str + # prints concatenated string Hello, World! Hai
STRINGS IN PYHON

5. PYTHON LIST,TUPLE AND DICTIONARY
 A List can hold items of different data types.
- The list is enclosed by square brackets [] where
the items are separated by commas
 Tuple is another sequence data type similar to list.
-A tuple consists of a number of values separated
by commas and enclosed within parentheses( )
Unlike list, the tuple values cannot be updated
 Dictionary is a kind of hash table. It contains key-value
pairs.
-Dictionaries are enclosed by curly braces {}

6. LIST IN PYTHON
Code Comment Result
print list1 # prints complete list [‘abcd’, 345,
3.2,’python’,
3.14]
print list1[0] # prints first element of the list abcd
print list1[-1] #prints last element of the list 3.14
print list1[1:3] # prints elements starting from index 1
2
# prints list1[start_at : end_at-1]
[345, 3.2]
print list1[2:] #prints list starting at index 2 till end of
the list
[3.2, ‘python’, 3.14]
print list 2 * 2 # asterisk (*) -is the repetition
Prints the list two times.
[‘abcd’, 345, 3.2,
‘python’,
3.14, 234, ‘xyz’]
print list1 + # prints concatenated lists [‘abcd’, 345,
3.2,’python’,
3.14, 234, ‘xyz’]

7. TUPLES IN PYTHON
Code Comment Result
print tuple1 # prints complete tuple1 (‘abcd’, 345, 3.2,
3.14)
print tuple1[0] # prints first element of the tuple1 abcd
print tuple1[-1] #prints last element of the tuple1 3.14
print # prints elements starting from index 1
# prints tuple1[start_at : end_at-1]
(345, 3.2)
print tuple1[2:] #prints tuple1 starting at index 2 till the
end
(3.2, ‘python’, 3.14)
print tuple 2 * 2 # asterisk (*) -is the repetition operator.
Prints the tuple2 two times.
(234, 'xyz', 234, 'xyz')
print tuple1 +
tuple2
# prints concatenated tuples (‘abcd’, 345,
3.14, 234, ‘xyz’)

8. DICTIONARY IN PYTHON
Code Comment Result
print dict1 # prints complete dictionary { ‘dept’: ‘Engg’,
‘code’:6734,
‘name’ : ‘ABCD’}
print dict1.keys() # prints all keys of dictionary { ‘dept’, ‘code’, ‘name’}
print dict1.values #prints all values of dictionary {‘Engg’, 6734, ‘ABCD’}
print dict2[‘rollno’] # print the value for the key
rollno
II-ITA24

9. OPERATORS –SUPPORTED BY PYTHON
 Python language supports the following types of operators.
• Arithmetic Operators
• Comparison (Relational) Operators
• Assignment Operators
• Logical Operators
• Bitwise Operators
• Membership Operators
• Identity Operators

10. MEMBERSHIP & IDENTITY OPERATORS
 Membership operators test for membership in a
sequence, such as strings, lists, or tuples and
explained below:
 Identity operators compare the memory locations of
two objects. MEMBERSHIP
OPERATOR
IDENTITY
OPERATOR
in is
not in is not

11. Membership Operartor
a = 6 b = 2
list = [1, 2, 3, 4, 5 ];
print a in list
print a not in list
print b in list
print b not in list
Output
False
True
True
False
IdentityOperartor
a = 20 b = 20
print a is b
print a is not b
b=30
print a is b
Output
True
False
False

12. ALIASING/ CLONNING
Aliasing
a=[1,2,3,4,5]
b=a
print(b)
 Cloning
a=[1,2,3,4,5]
b=a[:]
print(b)
 Another method
b=a.copy()

13. MODULES –USED TO REUSE THE CODE IN
MORE THAN ONE PROGRAM
 Math Module
c=math.sqrt(64)
d=math.log10(100.2)
print c
print d
Import Random
r=random.range(30)
print r
r=random.randint(0,5)
print r

14. FILE HANDLING
 Read(),write(),Open(),Close()..
Read Operation
f=open(“test.txt”,’r’)
data=f.read(10)
print(data)
f.close()
Write Operation
f=open(“test.txt”,’r’)
f.write(“python program”)
f.close()

15. PYTHON IN XML
 Extensible Markup Language (XML) is a markup
language which encodes documents by defining a
set of rules in both machine-readable and human-
readable format.
 Extended from SGML (Standard Generalized
Markup Language), it lets us describe the structure
of the document.
 In XML, we can define custom tags.
 XML is used as a standard format to exchange
information.

16. PYTHON XML PARSER
 <?xml version="1.0"?>
 <genre catalogue="Pop">
 <song title="No Tears Left to Cry">
 <artist>Ariana Grande</artist>
 <year>2018</year>
 <album>Sweetener</album>
 </song> Python XML file
 <song title="Delicate">
 <artist>Taylor Swift</artist>
 <year>2018</year>
 <album>Reputation</album>
 </song>
WE WILL MAKE USE OF TWO APIS TO DEAL WITH
PYTHON XML PARSER HERE- SAX AND DOM.

17. DOM PARSER
>>> from xml.dom.minidom import parse
>>> import xml.dom.minidom
>>> import os
>>> os.chdir('C:UserslifeiDesktop')
>>> DOMTree = xml.dom.minidom.parse("songs.xml") #Opening the XML
document
>>> genre=DOMTree.documentElement
>>> if genre.hasAttribute('catalogue'):
print(f'Root: {genre.getAttribute("catalogue")}')
Root: Pop
>>> songs=genre.getElementsByTagName('song') #Get all songs in the genre
Pop
>>> for song in songs: #Print each song’s details
print('Song:')
if song.hasAttribute('title'):
print(f'Title: {song.getAttribute("title")}')
artist=song.getElementsByTagName('artist')[0]
print(f'Artist: {artist.firstChild.data}')
year=song.getElementsByTagName('year')[0]
print(f'Release Year: {year.firstChild.data}')
album=song.getElementsByTagName('album')[0]
print(f'Album: {album.firstChild.data}')

18. PYTHON MATH LIBRARIES
 The most basic math module that is available in
Python.
 It covers basic mathematical operations like sum,
exponential, modulus, etc.
>>> from math import exp
>>> exp(3) #Calculates Exponential

19. USING NUMPY- ITS ABILITY TO PERFORM
LIGHTNING SPEED CALCULATIONS.
The numpy library in Python is most widely used for
carrying out mathematical operations that involve
matrices.
>>> import numpy as np
>>> mat1 = np.array([[1,2],[3,4]])
>>> mat2 = np.array([[5,6],[7,8]])
>>> np.dot(mat1,mat2)
array([[19, 22],
[43, 50]])

20. USING MATPLOTLIB
from matplotlib import pyplot as plt
#Plotting to our canvas
plt.plot([1,2,3],[4,5,1])
#Showing what we plotted
plt.show()