Python Revision Project - 1

Project Description

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This is a simple project where users can view, create, search, update and delete contacts through the CLI. The contact detail contains name, number and email, and the data is stored in a .txt file. The entire code of the project can be found in this GitHub Repo.

Project Detail

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The project structure is fairly simple and easy to follow.

ContactBookApplication/
│
├── main.py
├── contactManager.py
└── data/
    └── contactData.txt

The main.py is the file through which the project is initialized. It contains simple prompts that allow user to access various functionalities of the application. Similarly, contactManager.py contains functions that allow the user to view, create, update, delete and find contacts. Finally, the contactData.txt file contains all the contact data.

Here is the general description of each file:

# main.py
from contactManager import viewContacts, createContact, searchContact, updateContactDetail, deleteContact

print("Hello, Welcome to Contact Management System! \n")

userLoggedIn = True

while(userLoggedIn):
    userChoice = input("What would you like to do?\n1. View contacts\n2. Create new contact\n3. Find a contact\n4. Update existing contact\n5. Delete a contact\n6. Exit the program\nEnter: ")
    if userChoice == '1':
        viewContacts()
    elif userChoice == '2':
        createContact()
    elif userChoice == '3':
        userNamePrompt = input('Enter contact owner name: ')
        searchContact(userNamePrompt)
    elif userChoice == '4':
        userNumberPrompt = input('Enter the contact number: ')
        contactName = input("Enter new contact name: ")
        contactNumber = input("Enter new contact number: ")
        contactEmail = input("Enter new contact email: ")
        updateContactDetail(userNumberPrompt, contactName, contactNumber, contactEmail)
    elif userChoice == '5':
        userNumberPrompt = input('Enter contact number: ')
        deleteContact(userNumberPrompt)
    elif userChoice == '6':
        userLoggedIn = False
        print("Program ended successfully!\n")

The main.py contains prompts that allows the user to manipulate contacts. It is fairly straight forward. Option 1 to 5 allows user to view, create, search, update and delete contacts respectively. And option 6 just terminates the program.

# contactManager.py
import os

filePath = 'data/contactData.txt'

# view all contacts
def viewContacts():
    folderExist = os.path.isdir('data')
    fileExist = os.path.exists(filePath)

    if(folderExist and fileExist):
        with open(filePath, "r") as fileContent:
            print(fileContent.read())
    else:
        print('No contact details available!\n')

def userCreateContactPrompt():
    contactName = input("Enter contact name: ")
    contactNumber = input("Enter contact number: ")
    contactEmail = input("Enter contact email: ")
    contactData = f"{contactName}, {contactNumber}, {contactEmail}\n"

    with open(filePath, "a") as file:
        file.write(contactData)

    print("Contact created successfully!\n")

# create a contact
def createContact():
    # if folder doesnt exists
    # create the folder
    folderExist = os.path.isdir('data')

    if not folderExist:
        os.makedirs('data')
        userCreateContactPrompt()
        return

    else:
        # append the details provided by the user
        # also creates the file, if does not exists
        userCreateContactPrompt()
        return

# find/search a contact
def searchContact(contactName):
    with open(filePath, 'r') as file:
        lines = file.readlines()
        for line in lines:
            if line.find(contactName) != -1:
                print(line)
                return
        print('No such contact exists!\n')   

# update existing contact
def updateContactDetail(contactNumber, updatedName, updatedNumber, updatedEmail):
    updated_contact = f"{updatedName}, {updatedNumber}, {updatedEmail}\n"
    contactFound = False

    with open(filePath, "r+") as file:
        lines = file.readlines()
        file.seek(0) # file pointer at the beginning

        for index, line in enumerate(lines):
            if contactNumber in line:
                lines[index] = updated_contact
                contactFound = True

        file.writelines(lines)
        file.truncate()

    if contactFound:
        print('Contact detail updated successfully!\n')
    else:
        print('Contact detail not found!\n')

# delete existing contact
def deleteContact(contactNumber):
    with open(filePath, "r") as file:
        lines = file.readlines()

    with open(filePath, "w") as file:
        for line in lines:
            if contactNumber not in line:
                file.write(line)

    print('Contact deleted successfully!\n')

ContactManager.py contains the main logic of the application. I will briefly explain each method's functionality:

• viewContacts(): It displays the contact details stored in the contactData.txt file in the CLI. If no file or folder is found appropriate message is displayed.

• userCreateContactPrompt() : It takes contact name, number and email from the user and writes in the contactData.txt file. If the file does not exist, the write method automatically creates the file. For more information on the method you can reference this blog by freeCodeCamp.

• createContact() : It calls the userCreateContactPrompt() method and creates the contact.

• searchContact() : It reads the file using readlines() method, which returns an array of strings for each line. Then by using for loop, the name provided by the user as a prompt is searched in the contactData.txt file and the first occurrence is displayed. If no contact is found appropriate message is displayed.

• updateContactDetail() : It accepts the contact number and new name, number and email from the user. After going through the array of lines, if the provided contact number matches, it is replaced by the new data provided by the user.

• deleteContact() : It takes contact number as a parameter. Then after reading the file, it goes through the array of strings to write into the file except the line that contains the number provided by the user.

Insights

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I decided to create this simple program to familiarize myself with the python syntax. The program is not perfect, not at all 😬. There are many ideal conditions that I have assumed, some of them being:

• User will always input valid contact number and email

• There will be no duplicate contact name, number or email

• User will always input prompt between 1 and 6

So, the program can be definitely improved. Even viewing the data can be further improved. I've just printed the contents of the text file without even structuring them in a tabular format to make it more readable.

Conclusion

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Concluding, feel free to update the code which can be found easily in my repository. This small and simple project was a great refresher to python. I will be doing a couple more refresher projects so see ya later 👋.