PhoneDirectory.py

# importing the module
import sys

# this function will be the first to run as soon as the main function executes
def initial_phonebook():
	rows, cols = int(input("Please enter initial number of contacts: ")), 5
	
	# We are collecting the initial number of contacts the user wants to have in the
	# phonebook already. User may also enter 0 if he doesn't wish to enter any.
	phone_book = []
	print(phone_book)
	for i in range(rows):
		print("\nEnter contact %d details in the following order (ONLY):" % (i+1))
		print("NOTE: * indicates mandatory fields")
		print("....................................................................")
		temp = []
		for j in range(cols):
					
		# We have taken the conditions for values of j only for the personalized fields
		# such as name, number, e-mail id, dob, category etc
			if j == 0:
				temp.append(str(input("Enter name*: ")))
				
				# We need to check if the user has left the name empty as its mentioned that
				# name & number are mandatory fields.
				# So implement a condition to check as below.
				if temp[j] == '' or temp[j] == ' ':
					sys.exit(
						"Name is a mandatory field. Process exiting due to blank field...")
					# This will exit the process if a blank field is encountered.
					
			if j == 1:
				temp.append(int(input("Enter number*: ")))
				# We do not need to check if user has entered the number because int automatically
				# takes care of it. Int value cannot accept a blank as that counts as a string.
				# So process automatically exits without us using the sys package.
				
			if j == 2:
				temp.append(str(input("Enter e-mail address: ")))
				# Even if this field is left as blank, None will take the blank's place
				if temp[j] == '' or temp[j] == ' ':
					temp[j] = None
					
			if j == 3:
				temp.append(str(input("Enter date of birth(dd/mm/yy): ")))
				# Whatever format the user enters dob in, it won't make a difference to the compiler
				# Only while searching the user will have to enter query exactly the same way as
				# he entered during the input so as to ensure accurate searches
				if temp[j] == '' or temp[j] == ' ':
									
				# Even if this field is left as blank, None will take the blank's place
					temp[j] = None
			if j == 4:
				temp.append(
					str(input("Enter category(Family/Friends/Work/Others): ")))
				# Even if this field is left as blank, None will take the blank's place
				if temp[j] == "" or temp[j] == ' ':
					temp[j] = None
					
		phone_book.append(temp)
		# By this step we are appending a list temp into a list phone_book
		# That means phone_book is a 2-D array and temp is a 1-D array
	
	print(phone_book)
	return phone_book

def menu():
	# We created this simple menu function for
	# code reusability & also for an interactive console
	# Menu func will only execute when called
	print("********************************************************************")
	print("\t\t\tSMARTPHONE DIRECTORY")
	print("********************************************************************")
	print("\tYou can now perform the following operations on this phonebook\n")
	print("1. Add a new contact")
	print("2. Remove an existing contact")
	print("3. Delete all contacts")
	print("4. Search for a contact")
	print("5. Display all contacts")
	print("6. Exit phonebook")

	# Out of the provided 6 choices, user needs to enter any 1 choice among the 6
	# We return the entered choice to the calling function wiz main in our case
	choice = int(input("Please enter your choice: "))
	
	return choice

def add_contact(pb):
	# Adding a contact is the easiest because all you need to do is:
	# append another list of details into the already existing list
	dip = []
	for i in range(len(pb[0])):
		if i == 0:
			dip.append(str(input("Enter name: ")))
		if i == 1:
			dip.append(int(input("Enter number: ")))
		if i == 2:
			dip.append(str(input("Enter e-mail address: ")))
		if i == 3:
			dip.append(str(input("Enter date of birth(dd/mm/yy): ")))
		if i == 4:
			dip.append(
				str(input("Enter category(Family/Friends/Work/Others): ")))
	pb.append(dip)
	# And once you modify the list, you return it to the calling function wiz main, here.
	return pb

def remove_existing(pb):
	# This function is to remove a contact's details from existing phonebook
	query = str(
		input("Please enter the name of the contact you wish to remove: "))
	# We'll collect name of the contact and search if it exists in our phonebook
	
	temp = 0
	# temp is a checking variable here. We assigned a value 0 to temp.
	
	for i in range(len(pb)):
		if query == pb[i][0]:
			temp += 1
			# Temp will be incremented & it won't be 0 anymore in this function's scope
			
			print(pb.pop(i))
			# The pop function removes entry at index i
			
			print("This query has now been removed")
			# printing a confirmation message after removal.
			# This ensures that removal was successful.
			# After removal we will return the modified phonebook to the calling function
			# which is main in our program
			
			return pb
	if temp == 0:
		# Now if at all any case matches temp should've incremented but if otherwise,
		# temp will remain 0 and that means the query does not exist in this phonebook
		print("Sorry, you have entered an invalid query.\
	Please recheck and try again later.")
		
		return pb

def delete_all(pb):
	# This function will simply delete all the entries in the phonebook pb
	# It will return an empty phonebook after clearing
	return pb.clear()

def search_existing(pb):
	# This function searches for an existing contact and displays the result
	choice = int(input("Enter search criteria\n\n\
	1. Name\n2. Number\n3. Email-id\n4. DOB\n5. Category(Family/Friends/Work/Others)\
	\nPlease enter: "))
	# We're doing so just to ensure that the user experiences a customized search result
	
	temp = []
	check = -1
	
	if choice == 1:
	# This will execute for searches based on contact name
		query = str(
			input("Please enter the name of the contact you wish to search: "))
		for i in range(len(pb)):
			if query == pb[i][0]:
				check = i
				temp.append(pb[i])
				
	elif choice == 2:
	# This will execute for searches based on contact number
		query = int(
			input("Please enter the number of the contact you wish to search: "))
		for i in range(len(pb)):
			if query == pb[i][1]:
				check = i
				temp.append(pb[i])
				
	elif choice == 3:
	# This will execute for searches based on contact's e-mail address
		query = str(input("Please enter the e-mail ID\
		of the contact you wish to search: "))
		for i in range(len(pb)):
			if query == pb[i][2]:
				check = i
				temp.append(pb[i])
				
	elif choice == 4:
	# This will execute for searches based on contact''s date of birth
		query = str(input("Please enter the DOB (in dd/mm/yyyy format ONLY)\
			of the contact you wish to search: "))
		for i in range(len(pb)):
			if query == pb[i][3]:
				check = i
				temp.append(pb[i])
				
	elif choice == 5:
	# This will execute for searches based on contact category
		query = str(
			input("Please enter the category of the contact you wish to search: "))
		for i in range(len(pb)):
			if query == pb[i][4]:
				check = i
				temp.append(pb[i])
		# All contacts under query category will be shown using this feature
		
	else:
	# If the user enters any other choice then the search will be unsuccessful
		print("Invalid search criteria")
		return -1
	# returning -1 indicates that the search was unsuccessful
	
	# all the searches are stored in temp and all the results will be displayed with
	# the help of display function
	
	if check == -1:
		return -1
		# returning -1 indicates that the query did not exist in the directory
	else:
		display_all(temp)
		return check
		# we're just returning a index value wiz not -1 to calling function just to notify
		# that the search worked successfully

# this function displays all content of phonebook pb
def display_all(pb):
	if not pb:
	# if display function is called after deleting all contacts then the len will be 0
	# And then without this condition it will throw an error
		print("List is empty: []")
	else:
		for i in range(len(pb)):
			print(pb[i])

def thanks():
# A simple gesture of courtesy towards the user to enhance user experience
	print("********************************************************************")
	print("Thank you for using our Smartphone directory system.")
	print("Please visit again!")
	print("********************************************************************")
	sys.exit("Goodbye, have a nice day ahead!")

# Main function code
print("....................................................................")
print("Hello dear user, welcome to our smartphone directory system")
print("You may now proceed to explore this directory")
print("....................................................................")
# This is solely meant for decoration purpose only.
# You're free to modify your interface as per your will to make it look interactive

ch = 1
pb = initial_phonebook()
while ch in (1, 2, 3, 4, 5):
	ch = menu()
	if ch == 1:
		pb = add_contact(pb)
	elif ch == 2:
		pb = remove_existing(pb)
	elif ch == 3:
		pb = delete_all(pb)
	elif ch == 4:
		d = search_existing(pb)
		if d == -1:
			print("The contact does not exist. Please try again")
	elif ch == 5:
		display_all(pb)
	else:
		thanks()