Question

For Python-3

I need help with

First creating a text file named "items.txt" that has the following data in this order: Potatoes Tomatoes Carrots.

Write a python program that

1. Puts this as the first line... import os

2. Creates an empty list

3. Defines main() function that performs the tasks listed below when called.

4. Put these two lines at the top of the main function... if os.path.exists("costlist.txt"): os.remove("costlist.txt")

Note: This removes the "costlist.txt" file, if it exists.

5. Display "Assignment 6"

6. Prompts the user to enter a file name.

a. If the file name entered is "end" then end the program.

b. If the file name is "items.txt", open the file for reading, replace all the newline characters with an empty string, and add all of the items from the file to the list that was defined in step #2

c. If a FileNotFoundError exception occurs, display a message that lets the user know the file was not found and gives them a chance to try it again.

7. Sort the list.

8. For each element in the list, prompt the user to enter the price for the element, e.g. How much should Carrots cost? Convert the number entered into a float.

a. If the number entered does not convert properly into a float, and gets a ValueError exception, then display a couple error messages in the following format... You entered an invalid float that could not convert string to float: 'ss' Skipping to the next item after (element) ... and then prompt the user to enter the price of the next element from the list.

b. If the number does convert properly to a float then create a string variable with the following format... (element) have a cost of (cost) dollars ... and open the "costlist.txt" file for appending and write the string created to a line in the file.

9. Display "Cost List"

10. Display each line from the "costlist.txt" file

11. Display "Program End"

Below is a example of how the program might run, the program should run in a similar manner no matter what names and age are entered.

Example Run #1:

Assignment 6

Enter file name end

Program Ended

Example Run #2:

Assignment 6

Enter file name items.txt

How much should Carrots cost? ss

You entered an invalid float that could not convert string to float: 'ss' Skipping to the next item after Carrots

How much should Potatoes cost? 77

How much should Tomatoes cost? 44

Cost List:

Potatoes have a cost of 77.0 dollars

Tomatoes have a cost of 44.0 dollars

Program End Example

Run #3:

Assignment 6

Enter file name aa.txt

Could not find file named aa.txt. Please Try Again

Enter file name items.txt

How much should Carrots cost? 11.23

How much should Potatoes cost? 4.77

How much should Tomatoes cost? 7.99

Cost List:

Carrots have a cost of 11.23 dollars

Potatoes have a cost of 4.77 dollars

Tomatoes have a cost of 7.99 dollars

Program End

Answer 1

Python Program:

import os

def main():
   """ Main function """
   # Empty items list
   items = []
  
   if os.path.exists("costlist.txt"):
       os.remove("costlist.txt")
      
   print("Assignment 6")

   loop = True
   # Loop till user enters valid file name
   while loop:  
       # Reading file name
       fName = input("Enter file name: ")
      
       try:      
           # Checking file name
           if fName.lower() == "end":
               print("Program Ended")
               return
          
           else:
               # Opening file for reading
               fp = open(fName, "r")
               loop = False
               # Replace all the newline characters with an empty string  
               for line in fp:
                   line = line.strip()
                   # Adding items to list
                   for item in line.split(' '):
                       items.append(item)
              
               # Closing file
               fp.close()
              
               # Sorting items
               items.sort()
              
               # Opening file for appending
               opFile = open("costlist.txt", "w")
                  
               # Reading cost
               for item in items:
                   try:  
                       cost = float(input("How much should " + item + " cost? "))
                       # Writing to file
                       opFile.write(item + " have a cost of " + str(cost) + " dollars\n")
                   except ValueError:
                       print("You entered an invalid float that could not convert string to float: 'ss' Skipping to the next item after " + item + "\n")
              
               # Closing output file
               opFile.close()
              
               print("Cost List: ")
              
               # Reading and printing data from cost file
               ipFile = open("costlist.txt", "r")
              
               # Reading and printing text
               for line in ipFile:
                   line = line.strip()
                   print(line)
                  
               # Closing input file
               ipFile.close()
              
               print("Program End")
          
       except FileNotFoundError:
           print("Could not find file named " + fName + ". Please Try Again")
              
              
              
# Calling main function
main()

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Sample Run:

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Code Screenshot: