CLASS 12 : PRACTICAL FILE PROGRAMS

Question: 16

Write a python program to read a file named “story.txt”, count and print total lines starting with vowels in the file?

Sol:

filepath = 'story.txt'
vowels="AEIOUaeiou"
with open(filepath) as fp:
    line = fp.readline()
    cnt = 1
    while line:
        if(line[0] in vowels):
            #print(line)
            print("Line {}: {}".format(cnt, line.strip()))
            cnt=cnt+1
        line = fp.readline() 

Output:

Line 1: amit
Line 2: owl
Line 3: Eat apple a day and stay healthy
Line 4: Anmol
>>>

Question: 17

Python program to plot a sine wave using a line chart

Sol:

#program to plot a sine wave using a line chart
import matplotlib.pyplot as plt
import numpy as np
xvals=np.arange(-2,1,0.01)
yvals=np.sin(xvals) #evaluate function on xvals
create line plot with xvals and yvals
plt.plot(xvals,yvals)
show the grid
plt.grid(True)
plt.show() 

Output:

Question:18

Python program to plot bar chart

Sol:

#program to plot bar chart
import matplotlib.pyplot as plt
import numpy as np
objects=("python","c++","Java","Perl","C","Lisp")
y_pos=np.arange(len(objects))
performance=[10,8,5,4,2,1]
plt.xlabel="Usage"
plt.ylabel="Languages"
plt.title("Programming language usage")
plt.bar(y_pos,performance,align="center",width=.5, color='r')
plt.barh(y_pos,performance,align="center", color='r')
plt.show() 

Output:

Question:19

Python interface with MySQL

Write a function to insert a record in table using python  and MySQL interface.

Sol:

def insert_data():
     #take input for the details and then save the record in the databse
     #to insert data into the existing table in an existing database
     import pymysql
     # Open database connection
     #conn=pymysql.connect(host='localhost',user='root',password='',db='test')
     db = pymysql.connect("localhost","root","","test4")
     # prepare a cursor object using cursor() method
     c = db.cursor()
     r=int(input("Enter roll no "))
     n=input("Enter name ")
     p=int(input("Enter per "))
     try:
         # execute SQL query using execute() method.
         c.execute("insert into student (roll,name,per) values (%s,%s,%s)",(r,n,p))
         #to save the data
         db.commit()
         print("Record saved")
     except:
         db.rollback()
         # disconnect from server
     db.close()
# function calling
 insert_data()

Output:

Enter roll no 101
Enter name amit
Enter per 97
Record saved
>>>

Program 20:

Python interface with MySQL

Write a function to display all the records stored in a table using python  and MySQL interface.

Sol:

def display_all():
     #display the records from a table
     #field by field
     import pymysql
     # Open database connection
     #conn=pymysql.connect(host='localhost',user='root',password='',db='test')
     db = pymysql.connect("localhost","root","","test4")
     # prepare a cursor object using cursor() method
     try:
         c = db.cursor()
         sql='select * from student;'
         c.execute(sql)
         countrow=c.execute(sql)
         print("number of rows : ",countrow)
         #data=a.fetchone()
         data=c.fetchall()
         #print(data)
         print("=========================")
         print("Roll No     Name     Per ")
         print("=========================")
         for eachrow in data:
             r=eachrow[0]
             n=eachrow[1]
             p=eachrow[2]
             # Now print fetched result
             print(r,'      ',n,'    ',p)
         print("=========================")
     except:
         db.rollback()
     # disconnect from server
     db.close()
# function calling
display_all()

Output:

number of rows : 2
=========================
Roll No Name Per
=========================
102 aaa 99
101 amit 97
=========================
>>>

Program :21

Python interface with MySQL

Write a function to search a record stored in a table using python  and MySQL interface.

Sol:

def search_roll():
     #searching a record by roll no
     #display the records from a table
     #field by field
     import pymysql
     # Open database connection
     #conn=pymysql.connect(host='localhost',user='root',password='',db='test')
     db = pymysql.connect("localhost","root","","test4")
     # prepare a cursor object using cursor() method
     try:
         z=0
         roll=int(input("Enter roll no to search "))
         c = db.cursor()
         sql='select * from student;'
         c.execute(sql)
         countrow=c.execute(sql)
         print("number of rows : ",countrow)
         #data=a.fetchone()
         data=c.fetchall()
         #print(data)
         for eachrow in data:
             r=eachrow[0]
             n=eachrow[1]
             p=eachrow[2]
             # Now print fetched result
             if(r==roll):
                 z=1
                 print(r,n,p)
         if(z==0):
             print("Record is not present")
     except:
         db.rollback()
     # disconnect from server
     db.close()
# function calling
 search_roll()

Output:

Enter roll no to search 101
number of rows : 2
101 amit 97
>>>

CBSE Class 12 @ Python

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Functions (Funcations, Inbuilt Functions, Python Modules, Python Packages)

Inbuilt Functions

Python Modules

Python Packages

Using Python Libraries

Python Data File Handling

Program Efficiency

Data Structures In Python

Data Visualization Using Pyplot

Computer Networks

MySQL

Interface Python with SQL

Society, Law and Ethics

Web Development with Django

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