Question

PYTHON . John Zelle – 3rd Edition

Chapter 12

Object-Oriented Design

(Programming Exercise on page 458)

Q3

Write a program to keep track of conference attendees. For each attendee, your program should keep track name, company, state, and email address. Your program should allow users to do things such as add a new attendee, display information on an attendee, delete an attendee, list the names and email addresss of all attendees, and list the names and email addresses of all attendees from a given state. The attendee list should be stored in a file and loaded when the program starts.

Answer 1

'''

Comment if you have any doubts and Please Like The Answer

'''

'''
File Name: Attendee.py
'''
class Attendee:
   def __init__(self,name,company,state,email):
       self.name = name.title()
       self.company = company.title()
       self.state = state.upper()
       self.email = email.lower()
  
   def __str__(self):
       return "\n{0:^15} {1:^15} {2:^15} {3:^15}".format(self.name,self.company,self.state,self.email)

'''
File Name: Attendees.py
'''
from Attendee import Attendee
class Attendees:
   def __init__(self):
       self.attendees = []
       self.count = 0
   def addAttendee(self,attendee):
       if(type (attendee) == Attendee):
           self.attendees.append(attendee)
           self.count+= 1
       else:
           print("\nNeed Attendee object.")
  
   def deleteAttendee(self,email):
       email = email.lower()
       for i,attendee in enumerate(self.attendees):
           if(attendee.email.lower() == email):
               att = self.attendees.pop(i)
               self.count-=1
               print("\nSuccessfully Deleted attendee with: ",att)
               return None
               break
       print("\nEmail:",email,"Not Found")
  
   def displayAttendeeByName(self,name):
       print("\nList of attendees having name:",name)
      
       name = name.lower()
       found = False
       for i,attendee in enumerate(self.attendees):
           if(name in attendee.name.lower()):
               if(not found):
                   print("--------------------------------------------------------------------\n")
                   print("\n{0:^15} {1:^15} {2:^15} {3:^15}".format("Name","Company","State","Email"))
                   print("\n--------------------------------------------------------------------\n")
               print("\n{0:^15} {1:^15} {2:^15} {3:^15}".format(attendee.name,attendee.company,attendee.state,attendee.email))
               found = True
       if(not found):
           print("\nList is Empty")
           return None
       print("\n--------------------------------------------------------------------\n")
   def displayAttendeeByNamesAndEmails(self):
       print("\nTotal Attendees :",self.count)
      
       if(self.count == 0):
           print("\nList is Empty")
           return None
       print("--------------------------------------------------------------------\n")
       print("\n{0:^15} {1:^15}".format("Name","Email"))
       print("\n--------------------------------------------------------------------\n")
       for i,attendee in enumerate(self.attendees):
           print("\n{0:^15} {1:^15}".format(attendee.name,attendee.email))
       print("\n--------------------------------------------------------------------\n")
   def displayAttendeeByState(self,state):
       print("\nList of attendees from State :",state)
       found = False
       state = state.lower()
       for i,attendee in enumerate(self.attendees):
           if(state in attendee.state.lower()):
               if(not found):
                   print("--------------------------------------------------------------------\n")
                   print("\n{0:^15} {1:^15} {2:^15} {3:^15}".format("Name","Company","State","Email"))
                   print("\n--------------------------------------------------------------------\n")
               print("\n{0:^15} {1:^15} {2:^15} {3:^15}".format(attendee.name,attendee.company,attendee.state,attendee.email))
               found = True
       if(not found):
           print("\nList is Empty")  
           return None
       print("\n--------------------------------------------------------------------\n")
   def storeList(self,fileName):
       print()
       try:
           f = open(fileName,"w")
           for attendee in self.attendees:
               print("Writing to file : {},{},{},{}\n".format(attendee.name,attendee.company,attendee.state,attendee.email))
               f.write("{},{},{},{}\n".format(attendee.name,attendee.company,attendee.state,attendee.email))
           f.close()
       except Exception as e:
           print("\nError occured while writing data to file:",fileName)
      
   def readList(self,fileName):
       try:
           loaded = 0
           f = open(fileName,"r")
           line = f.readline()
           while(line):
               line = line.strip()
               data = line.split(",")
               if(len(data) != 4):
                   print("\nline :",line,"has invalid number of fields")
               else:
                   if(not self.is_array_has_empty_string(data)):
                       att =Attendee(data[0],data[1],data[2],data[3])
                       print("Adding: ",att)
                       self.addAttendee(att)
                       self.count+=1
                       loaded+= 1
               line = f.readline()
       except Exception as e:
           print("\nError occured while writing data to file:",fileName)
       print("\nLoaded:",loaded,"Attendees from file :",fileName)
  
   def is_array_has_empty_string(self,arr):
       has = False
       for i in arr:
           if(i.strip() == ""):
               has = True
               break
       return has

'''
File Name: conference.py
'''
from Attendees import Attendees
from Attendee import Attendee
def display_menu():
   print("\nConference Management.\n")
   print("\n1. Add Attendee")
   print("2. Delete Attendee by Email")
   print("3. Display Attendee by Name")
   print("4. Display All Attendees Names and Emails")
   print("5. Display Attendees by State")
   print("0. Quit")
   print("Enter your choice: ",end="" )

def get_choice():
   is_valid = False
   choice = -1
   while(not is_valid):
       display_menu()
       try:
           choice = int(input("").strip())
           is_valid = True
       except Exception as e:
           print("\nInvalid choice. try again")
   return choice

def is_array_has_empty_string(arr):
   has = False
   for i in arr:
       if(i.strip() == ""):
           has = True
           break
   return has
def get_attendee():
   print()
   name = input("Enter Attendee Name : ").strip()
   company = input("Enter Attendee Company : ").strip()
   state = input("Enter Attendee State : ").strip()
   email = input("Enter Attendee Email: ").strip()
   if(is_array_has_empty_string([name,company,state,email])):
       print("\nEach Information of Attendee must not empty and must not contain only spaces. Try again")
       return None
   else:
       return Attendee(name,company,state,email)
def manage_confernce():
   conference = Attendees()
   conference.readList("conference.txt")
   choice = -1
   while(choice != 0):
       choice = get_choice()
       if(choice == 1):
           att = get_attendee()
           if(att != None):
               conference.addAttendee(att)
       elif(choice == 2):
           email = input("\nEnter email of the Attendee to remove: ").strip()
           conference.deleteAttendee(email)
       elif(choice == 3):
           name = input("\nEnter Name of the Attendee to Display: ").strip()
           conference.displayAttendeeByName(name)
       elif(choice == 4):
           conference.displayAttendeeByNamesAndEmails()
       elif(choice == 5):
           state = input("\nEnter State of the Attendees to Display: ").strip()
           conference.displayAttendeeByState(state)
   conference.storeList("conference.txt")
   print("\nThank You.")
def main():
   manage_confernce()
if __name__ == "__main__":
   main()

---------------- after output conference.txt --------

John Wick,Smiths,UK,john@wick.com
Tony Stark,Stark Industries,USA,tony@avengers.com
Ant Man,Pim Tech,USA,ant@man.com