R20 PYTHON PROGRAMMING LAB (26-34 Programs)

26. Write a program that reads a list of temperatures from a file called temps.txt, converts those temperatures to Fahrenheit, and writes the results to a file called ftemps.txt.

fo = open("temps.txt")
f1= open("ftemps.txt","w+")
for i in fo:
    c=float(i)
    F=(9*c + (32*5))/5
    f1.write(str(F)+"\n")
f1.close()
fo.close()

27. Write a class called Product. The class should have fields called name, amount, and price, holding the product's name, the number of items of that product in stock, and the regular price of the product. There should be a method get_price that receives the number of items to be bought and returns a the cost of buying that many items, where the regular price is charged for orders of less than 10 items, a 10% discount is applied for orders of between 10 and 99 items, and a 20% discount is applied for orders of 100 or more items. There should also be a method called make_purchase that receives the number of items to be bought and decreases amount by that much.

class Product:
    def __init__(self,name,amount,price):
        self.name=name
        self.amount=amount
        self.price=price
        
    def get_price(self,number_items):
        if number_items<10:
            return self.price*number_items
        elif 10 <=number_items < 100:
            return 0.9*self.price*number_items
        else:return 0.8*self.price*number_items
    
    def make_purchase(self, quantity):
        self.amount -= quantity

name, amount, price = 'shoes', 200, 1200

shoes = Product(name, amount, price)

q1 = 4
print(f'cost for {q1} {shoes.name} = {shoes.get_price(q1)}')
shoes.make_purchase(q1)
print(f'remaining stock: {shoes.amount}\n')

q2 = 12
print(f'cost for {q2} {shoes.name} = {shoes.get_price(q2)}')
shoes.make_purchase(q2)
print(f'remaining stock: {shoes.amount}\n')

q3 = 112
print(f'cost for {q3} {shoes.name} = {shoes.get_price(q3)}')
shoes.make_purchase(q3)
print(f'remaining stock: {shoes.amount}\n')

28. Write a class called Time whose only field is a time in seconds. It should have a method called convert_to_minutes that returns a string of minutes and seconds formatted as in the following example: if seconds is 230, the method should return '5:50'. It should also have a method called convert_to_hours that returns a string of hours, minutes, and seconds formatted analogously to the previous method.

class Time():
   # constructor
   def __init__(self, seconds):
       self.seconds = seconds
  
   # function to convert and return a string of minutes and seconds
   def convert_to_minutes(self):
       mins = self.seconds//60 # get the total minutes in the given seconds
       secs = self.seconds - (mins*60) # get the remaining seconds
       print("{}:{} minutes".format(self.seconds//60,self.seconds%60))
       # return the string of minutes:seconds
       return "%d:%d minutes" %(mins,secs)
  
   # function to convert and return string of hours, minutes, and seconds
   def convert_to_hours(self):
       secs = self.seconds
       hours = secs//3600 # get the total hours in the given seconds
       secs = secs - (hours*3600) # get the remaining seconds
       mins = secs//60 # get the total minutes in the remaining seconds
       secs = secs - (mins*60) # get the remaining seconds
       print("{:.2f} Hors".format(self.seconds/3600))
       # return the string of hours:minutes:seconds
       return "%d:%d:%d" %(hours,mins,secs)
      
time = Time(365)
print(time.convert_to_minutes())
time = Time(4520)
print(time.convert_to_hours())

29. Write a class called Converter. The user will pass a length and a unit when declaring an object from the class for example, c = Converter(9,'inches'). The possible units are inches, feet, yards, miles, kilometers, meters, centimeters, and millimeters. For each of these units there should be a method that returns the length converted into those units. For example, using the Converter object created above, the user could call c.feet() and should get 0.75 as the result.

 class Converter:
    def __init__(self, n,name):
        self.value = n
        self.name=name
    
    def FeettoInches(self):
        Inches=self.value*12
        print("Feet to Inches value is ", Inches)
        
    def milestokm(self):
        km=self.value/0.62137
        print("miles to KM  is ", km)
            
    def FeettoYards(self):
        Yards= self.value * 0.3333
        print("Feet to Yards value is ", Yards)
    
    def FeettoMiles(self):
        Miles= self.value * 0.00018939
        print("Feet to Miles value is ", Miles)     
        
n=float(input("enter feet/inches/cm/mm/km/miles: "))
x=Converter(n,'inches')

x.FeettoInches()
x.milestokm()
x.FeettoYards()
x.FeettoMiles()

30. Write a Python class to implement pow(x, n).

class power:
    
    def pow1(self, x, n):
        if x==0 or x==1 or n==1:
            return x 

        if x==-1:
            if n%2 ==0:
                return 1
            else:
                return -1
        if n==0:
            return 1
        if n<0:
            return 1/self.pow1(x,-n)
        val = self.pow1(x,n//2)
        if n%2 ==0:
            return val*val
        return val*val*x

x=power()
print(x.pow1(2, -2))
print(x.pow1(3, 5))
print(x.pow1(100, 0))

31. Write a Python class to reverse a string word by word.

class py_solution:
    def reverse_words(self, s):
        return ' '.join(reversed(s.split()))


print(py_solution().reverse_words('hello .py'))

or

string = "I am a python programmer"
words = string.split()
words = list(reversed(words))
print(" ".join(words))

32. Write a program that opens a file dialog that allows you to select a text file. The program then displays the contents of the file in a textbox.

from tkinter import *
from tkinter.filedialog import *
from tkinter.scrolledtext import ScrolledText
#lab program 2 type
root = Tk()
root.title('File dialog') 
textbox = ScrolledText()
textbox.grid()

filename=askopenfilename(initialdir='C:\Python_Code\examples',filetypes=[('Text files', '.txt'),('All files', '*')])
s = open(filename).read()
textbox.insert(1.0, s)
mainloop()

or

from tkinter import *
from tkinter.filedialog import *
from tkinter import filedialog
from tkinter.scrolledtext import ScrolledText
#lab program 1 type
master = Tk()
master.title('File dialog')
textbox = ScrolledText()
textbox.grid()

def callback():
    filename=askopenfilename()
    s = open(filename).read()
    textbox.insert(1.0, s)
 
errmsg = 'Error!'
bt=Button(text='File Open', command=callback)
bt.grid(column=1, row=0)
mainloop()

33. Write a program to demonstrate Try/except/else

try:
    x=int(input('Enter a number upto 100: '))
    if x > 100:
        raise ValueError(x)
except ValueError: 
    print(x, "is out of allowed range")
else:
    print(x, "is within the allowed range")

34. Write a program to demonstrate try/finally and with/as.

try/finally

try:
    print('try block')
    x=int(input("Enter a number:"))
    y=int(input("Enter another number:"))
    z=x/y
except ZeroDivisionError:
    print("except ZeroDivisionError block") 
    print("Division by not accepted")
else:
    print("else block")
    print("Division = ", z)
finally:
    print("finally block")
    
print ("Out of try, except, else and finally blocks." )

Output1:
try block
Enter a number:100
Enter another number:10
else block
Division =  10.0
finally block
Out of try, except, else and finally blocks.


Output2:
try block
Enter a number:100
Enter another number:0
except ZeroDivisionError block
Division by not accepted
finally block
Out of try, except, else and finally blocks.


with/as

# file handling

#1)without using with statement
file=open('123.txt','w')
file.write('hello world')
file.close()

#2)with try and finally
file=open('123.txt','w')
try:
	file.write('hello world')
finally:
	file.close()

#3)using with statement
with open('123.txt','w') as file:
	file.write('hello world')