BCA PART B 11. Create DataFramefrom Excel sheet using Pandas and Perform Operations on DataFrames

 

import pandas as pd

# making data frame from csv file

df = pd.read_excel("nba.xlsx")

# printing the first 10 rows of the dataframe

df[:10]

# Applying aggregation across all the columns

# sum and min will be found for each

# numeric type column in df dataframe

df.aggregate(['sum', 'min'])

Download and save in the progam directory

BCA PART B 10. Create Array using NumPy and Perform Operations on Array

 

import numpy as np

arr = np.arange(1,11)

print(arr)

# returns the sum of the numbers

print(arr + arr)

# returns the diff between the numbers

print(arr - arr)

# returns the multiplication of the numbers

print(arr * arr )

# the code will continue to run but shows an error

print(arr / arr )

BCA PART B 9. Drawing Histogram and Pie chart using Matplotlib

 

import matplotlib.pyplot as plt

import numpy as np

y = np.random.normal(170, 10, 250)

plt.hist(y)

plt.show()

x = [64.73,18.43,3.37,3.36,10.11]

labels = ['Chrome', 'Safari', 'Edge', 'Firefox', 'Others']

plt.pie(x, labels=labels,autopct='%.1f%%')

plt.show()

BCA PART B 8. Demonstrate usage of advance regular expression

 

import matplotlib.pyplot as plt

country = ['A', 'B', 'C', 'D', 'E']

gdp_per_capita = [45000, 42000, 52000, 49000, 47000]

plt.plot(country, gdp_per_capita)

plt.title('Per Capita GDP')

plt.xlabel('Name ')

plt.ylabel('GDP')

plt.show()

plt.bar(country, gdp_per_capita)

plt.title('Per Capita GDP')

plt.xlabel('Name ')

plt.ylabel('GDP')

plt.show()

BCA PART B 7. Demonstrate Exceptions in Python

 a=int(input('Enter value of a: '))

b=int(input('Enter value of b: '))

try:

print('a/b=',a/b)

except ZeroDivisionError:

print("Sorry, Zero in the denominator.")

BCA PART B 6. Create a GUI using Tkinter module

 

from tkinter import *

# create root window

root = Tk()

# root window title and dimension

root.title("Welcome to VVFGC")

# Set geometry(widthxheight)

root.geometry('350x200')

#adding a label to the root window

lbl = Label(root, text = "Are you a Student?")

lbl.grid()

# Execute Tkinter

root.mainloop()

BCA PART B 5. Create SQLite Database and Perform Operations on Tables

 

import sqlite3

# Connecting to sqlite

# connection object

connection_obj = sqlite3.connect('VVFGC.db')

# cursor object

cursor_obj = connection_obj.cursor()

# Drop the table if already exists.

cursor_obj.execute("DROP TABLE IF EXISTS BCA")

# Creating table

table = """ CREATE TABLE BCA (

Email VARCHAR(255) NOT NULL,

First_Name CHAR(25) NOT NULL,

Last_Name CHAR(25),

Score INT

); """

cursor_obj.execute(table)

print("Table is Ready")

# Close the connection

connection_obj.close()

BCA PART B 4. Demonstrate use of Dictionary

 

n = 10

# declare dictionary

numbers = {}

# run loop from 1 to n

for i in range(1, n+1):

numbers[i] = i * i

# print dictionary

print(numbers)

BCA PART B 3. Demonstrate use of List

 

list = [10, 20, 30, "VVFGC", "Mysuru"]

# printing list

print("List elements are: ", list)

# adding elements

list.append (40)

list.append (50)

list.append ("Bengaluru")

# printing list after adding elements

print("List elements: ", list)

# removing elements

list.pop () ;

# printing list

print("List elements: ", list)

# removing elements

list.pop () ;

# printing list

print("List elements: ", list)

BCA PART B 2. Demonstrate usage of advance regular expression

 

import re

t="A fat cat doesn't eat oat but a rat eats bats."

mo = re.findall("[force]at", t)

print(mo)

BCA PART B 1. Demonstrate usage of basic regular expression

 

import re

print("Usage of square bracket : ")

string = "The quick brown fox jumps over the lazy dog"

pattern = "[a-m]"

result = re.findall(pattern, string)

print(result)

pattern = r"^The"

print("\n\n Search the pattern "+pattern+" at the end of the string ")

match = re.search(pattern, string)

if match:

print("Match found!")

else:

print("Match not found.")

BCA PART A 10. Read and write into a file

 

def write_to_file(filename, data):

"""

Write data to a file.

Parameters:

filename (str): The name of the file to write to.

data (str): The data to write into the file.

"""

with open(filename, 'w') as file:

file.write(data)

print(f"Data written to file '{filename}' successfully.")

def read_from_file(filename):

"""

Read data from a file.

Parameters:

filename (str): The name of the file to read from.

Returns:

str: The data read from the file.

"""

with open(filename, 'r') as file:

data = file.read()

print(f"Data read from file '{filename}':")

return data

if __name__ == '__main__':

filename = input("Enter the name of the file: ")

# User choice for operation

print("\nChoose an operation:")

print("1. Write to the file")

print("2. Read from the file")

choice = input("Enter your choice (1/2): ")

if choice == '1':

# Writing to the file

data_to_write = input("Enter the data to write into the file: ")

write_to_file(filename, data_to_write)

elif choice == '2':

# Reading from the file

data = read_from_file(filename)

print(data)

else:

print("Invalid choice. Please enter 1 or 2.")

Output :

Enter the name of the file: test Choose an operation: 1. Write to the file 2. Read from the file Enter your choice (1/2): 1 Enter the data to write into the file: Good Morning. Welcome to Vidya Vikas Data written to file 'test' successfully.

Enter the name of the file: test Choose an operation: 1. Write to the file 2. Read from the file Enter your choice (1/2): 2 Data read from file 'test': Good Morning. Welcome to Vidya Vikas

Explanation :

In this program, two functions are defined:

• write_to_file:

  • Takes a filename and data as input.
  • Opens the file in write mode ('w'), which either creates the file if it doesn't exist or truncates the file if it already exists.
  • Writes the data to the file.
  • Closes the file automatically when the with block exits.

• read_from_file:

  • Takes a filename as input.
  • Opens the file in read mode ('r').
  • Reads the data from the file.
  • Closes the file automatically when the with block exits.
  • Returns the data read from the file.

In the example usage section of the program:

• The user is prompted to enter the filename.
• The user chooses to either write to the file or read from it.
• Depending on the user's choice:
  • For the write operation, the program prompts the user to enter the data to write to the file and then calls the write_to_file function.
  • For the read operation, the program calls the read_from_file function and prints the data read from the file.

BCA PART A 9. Implement Stack

 

A stack is a data structure that follows the Last-In-First-Out (LIFO) principle. You can implement a stack in Python without using the stack module by using a list to store the stack elements. Below is a program that demonstrates how to create a stack class, implement its methods, and interact with the stack:

class Stack:

def __init__(self):

"""Initialize an empty stack using a list."""

self.stack = []

def is_empty(self):

"""Check if the stack is empty."""

return len(self.stack) == 0

def push(self, item):

"""Add an item to the top of the stack."""

self.stack.append(item)

print(f"Pushed {item} onto the stack.")

def pop(self):

"""Remove and return the item from the top of the stack.

If the stack is empty, return None and print a message."""

if self.is_empty():

print("Stack is empty. Cannot pop an item.")

return None

else:

item = self.stack.pop()

print(f"Popped {item} from the stack.")

return item

def peek(self):

"""Return the item from the top of the stack without removing it.

If the stack is empty, return None and print a message."""

if self.is_empty():

print("Stack is empty. Cannot peek an item.")

return None

else:

return self.stack[-1]

def display(self):

"""Display the current contents of the stack."""

if self.is_empty():

print("Stack is empty.")

else:

print("Stack contents:", self.stack)

# Example usage

if __name__ == "__main__":

# Create a stack instance

my_stack = Stack()

# Perform operations on the stack

while True:

print("\nStack Operations:")

print("1. Push an item onto the stack")

print("2. Pop an item from the stack")

print("3. Peek at the top item of the stack")

print("4. Display the contents of the stack")

print("5. Exit")

choice = input("Enter your choice (1-5): ")

if choice == '1':

item = input("Enter the item to push onto the stack: ")

my_stack.push(item)

elif choice == '2':

my_stack.pop()

elif choice == '3':

top_item = my_stack.peek()

if top_item is not None:

print(f"Top item: {top_item}")

elif choice == '4':

my_stack.display()

elif choice == '5':

print("Exiting the program.")

break

else:

print("Invalid choice. Please enter a number between 1 and 5.")

Output :

Enter your choice (1-5): 3 Stack is empty. Cannot peek an item. Stack Operations: 1. Push an item onto the stack 2. Pop an item from the stack 3. Peek at the top item of the stack 4. Display the contents of the stack 5. Exit Enter your choice (1-5): 4 Stack is empty. Stack Operations: 1. Push an item onto the stack 2. Pop an item from the stack 3. Peek at the top item of the stack 4. Display the contents of the stack 5. Exit Enter your choice (1-5): 1 Enter the item to push onto the stack: 34 Pushed 34 onto the stack. Stack Operations: 1. Push an item onto the stack 2. Pop an item from the stack 3. Peek at the top item of the stack 4. Display the contents of the stack 5. Exit Enter your choice (1-5): 1 Enter the item to push onto the stack: 5 Pushed 5 onto the stack. Stack Operations: 1. Push an item onto the stack 2. Pop an item from the stack 3. Peek at the top item of the stack 4. Display the contents of the stack 5. Exit Enter your choice (1-5): 4 Stack contents: ['34', '5'] Stack Operations: 1. Push an item onto the stack 2. Pop an item from the stack 3. Peek at the top item of the stack 4. Display the contents of the stack 5. Exit Enter your choice (1-5): 2 Popped 5 from the stack. Stack Operations: 1. Push an item onto the stack 2. Pop an item from the stack 3. Peek at the top item of the stack 4. Display the contents of the stack 5. Exit Enter your choice (1-5): 5 Exiting the program.

Explanation

The program provided implements a stack data structure in Python using a list to store stack elements. Let's go through each part of the program to understand how it works:

Stack Class

The Stack class defines the stack data structure and its methods.

• __init__: This is the class constructor method. It initializes an empty list stack that will hold the stack elements.

• is_empty: This method returns True if the stack is empty (i.e., the list has length zero) and False otherwise.

• push: This method takes an item as an argument and adds it to the top of the stack using the append method of the list. It also prints a message indicating that the item was pushed onto the stack.

• pop: This method removes and returns the item from the top of the stack. If the stack is empty, it prints a message indicating that the stack is empty and returns None. Otherwise, it uses the pop method of the list to remove the last element and prints a message showing which item was popped.

• peek: This method returns the item from the top of the stack without removing it. If the stack is empty, it prints a message indicating that the stack is empty and returns None. Otherwise, it returns the last element in the list.

• display: This method displays the current contents of the stack by printing the list.

Example Usage

The example usage section of the program demonstrates how to use the Stack class:

• It first creates an instance of the Stack class called my_stack.

• It then enters an infinite loop that provides a menu of stack operations that the user can perform: push, pop, peek, display, and exit.

• Depending on the user's choice, the program performs the corresponding operation on the stack.

  • Push: The program prompts the user to enter an item and then pushes that item onto the stack using the push method.

  • Pop: The program calls the pop method to remove the top item from the stack and prints a message indicating which item was popped.

  • Peek: The program calls the peek method to view the top item of the stack and prints it.

  • Display: The program calls the display method to show the current contents of the stack.

  • Exit: The program breaks out of the loop and ends the program.

The program continues to loop, allowing the user to perform multiple operations on the stack, until the user chooses to exit the program.