Project: CSV Contact Manager in Python0%

Project: CSV Contact Manager in Python

Intermediate8 min read•Updated: 2026-10-01

Project: CSV Contact Manager

In this hands-on project, we will apply the advanced file handling techniques covered in this chapter—including csv.DictReader, csv.DictWriter, context managers, and robust error handling—to build a persistent Command-Line CSV Contact Manager.

1. Project Specifications & Requirements

The application will manage contact records and save them to contacts.csv. Key capabilities:

1
Data Persistence: Automatically reads from and writes to a structured CSV file.
2
Auto-Initialization: Gracefully initializes the CSV file with headers if it does not yet exist.
3
Core CRUD Operations:

Create: Add new contacts with validation.
Read: Display all contacts in a formatted table.
Search: Case-insensitive search by name or category.
Delete: Remove a contact by name and rewrite the updated dataset.

1
Safety: Handles missing files, invalid inputs, and file permissions without crashing.

2. Complete Application Code

1import csv
2import os
3 
4CSV_FILE = "contacts.csv"
5FIELDNAMES = ["name", "phone", "email", "category"]
6 
7 
8def initialize_storage():
  """Ensures the CSV file exists with the proper column headers."""
  if not os.path.exists(CSV_FILE):
      try:
          with open(CSV_FILE, mode="w", encoding="utf-8", newline="") as f:
              writer = csv.DictWriter(f, fieldnames=FIELDNAMES)
              writer.writeheader()
      except OSError as err:
          print(f"Error initializing contact database: {err}")
17 
18 
19def load_contacts():
  """Loads and returns all contacts as a list of dictionaries."""
  contacts = []
  try:
      with open(CSV_FILE, mode="r", encoding="utf-8", newline="") as f:
          reader = csv.DictReader(f)
          for row in reader:
              contacts.append(row)
  except FileNotFoundError:
      initialize_storage()
  except OSError as err:
      print(f"Error reading {CSV_FILE}: {err}")
  return contacts
32 
33 
34def save_contacts(contacts):
  """Overwrites the CSV file with the provided list of contact dictionaries."""
  try:
      with open(CSV_FILE, mode="w", encoding="utf-8", newline="") as f:
          writer = csv.DictWriter(f, fieldnames=FIELDNAMES)
          writer.writeheader()
          writer.writerows(contacts)
      return True
  except OSError as err:
      print(f"Failed to save contacts: {err}")
      return False
45 
46 
47def add_contact():
  """Prompts for contact details and appends to CSV."""
  print("\n--- Add New Contact ---")
  name = input("Enter Full Name: ").strip()
  phone = input("Enter Phone Number: ").strip()
  email = input("Enter Email Address: ").strip()
  category = input("Enter Category (Family/Work/Friend): ").strip().capitalize()
54 
  if not name or not phone:
      print("Error: Name and Phone number are required fields!")
      return
58 
  contacts = load_contacts()
  
  # Check for duplicate names
  if any(c["name"].lower() == name.lower() for c in contacts):
      print(f"A contact named '{name}' already exists.")
      return
65 
  new_contact = {
      "name": name,
      "phone": phone,
      "email": email or "N/A",
      "category": category or "General"
  }
72 
  contacts.append(new_contact)
  if save_contacts(contacts):
      print(f"Contact '{name}' added successfully!")
76 
77 
78def view_contacts():
  """Displays all contacts in a formatted table."""
  contacts = load_contacts()
  if not contacts:
      print("\nNo contacts found. Add one first!")
      return
84 
  print("\n" + "=" * 65)
  print(f"{'NAME':<20} | {'PHONE':<15} | {'CATEGORY':<10} | {'EMAIL'}")
  print("-" * 65)
  for c in contacts:
      print(f"{c['name']:<20} | {c['phone']:<15} | {c['category']:<10} | {c['email']}")
  print("=" * 65)
91 
92 
93def search_contact():
  """Searches contacts by name or category substring."""
  query = input("\nEnter search term (name or category): ").strip().lower()
  contacts = load_contacts()
  
  results = [
      c for c in contacts 
      if query in c["name"].lower() or query in c["category"].lower()
  ]
102 
  if not results:
      print(f"No contacts matching '{query}'.")
      return
106 
  print(f"\nFound {len(results)} match(es):")
  for c in results:
      print(f" - {c['name']} ({c['category']}): {c['phone']} | {c['email']}")
110 
111 
112def delete_contact():
  """Deletes a contact by exact name."""
  name_to_delete = input("\nEnter exact name of contact to delete: ").strip().lower()
  contacts = load_contacts()
  
  initial_count = len(contacts)
  updated_contacts = [c for c in contacts if c["name"].lower() != name_to_delete]
119 
  if len(updated_contacts) == initial_count:
      print(f"No contact found with name '{name_to_delete}'.")
  else:
      if save_contacts(updated_contacts):
          print("Contact deleted successfully.")
125 
126 
127def main_menu():
  """Main user interaction loop."""
  initialize_storage()
  
  while True:
      print("\n===== CONTACT MANAGER (CSV) =====")
      print("1. View All Contacts")
      print("2. Add New Contact")
      print("3. Search Contact")
      print("4. Delete Contact")
      print("5. Exit")
138 
      choice = input("Select an option (1-5): ").strip()
140 
      if choice == "1":
          view_contacts()
      elif choice == "2":
          add_contact()
      elif choice == "3":
          search_contact()
      elif choice == "4":
          delete_contact()
      elif choice == "5":
          print("Exiting Contact Manager. Goodbye!")
          break
      else:
          print("Invalid choice. Please choose between 1 and 5.")
154 
155 
156if __name__ == "__main__":
  main_menu()

3. Sample Execution Output

1===== CONTACT MANAGER (CSV) =====
21. View All Contacts
32. Add New Contact
43. Search Contact
54. Delete Contact
65. Exit
7Select an option (1-5): 2
8 
9--- Add New Contact ---
10Enter Full Name: Anita Desai
11Enter Phone Number: +91-9876543210
12Enter Email Address: anita@example.com
13Enter Category (Family/Work/Friend): Work
14Contact 'Anita Desai' added successfully!
15 
16===== CONTACT MANAGER (CSV) =====
171. View All Contacts
182. Add New Contact
193. Search Contact
204. Delete Contact
215. Exit
22Select an option (1-5): 1
23 
24=================================================================
25NAME                 | PHONE           | CATEGORY   | EMAIL
26-----------------------------------------------------------------
27Anita Desai          | +91-9876543210  | Work       | anita@example.com
28=================================================================

⚠️ Common Intermediate Mistakes & Gotchas

1. Corrupting Data During Mid-Write Crashes

Writing directly to the target CSV file risks truncating existing data if the script crashes mid-write. In mission-critical systems, write to a temporary file first and atomically replace the destination with os.replace().

2. Case-Sensitive Search Mismatches

Always normalize search strings and contact names using .lower().strip() before comparison to ensure reliable search results.

💻 Try It Yourself: Extension Challenge - Contact Export

Challenge

Extend the Contact Manager to add a search filter method that finds contacts by company domain name (e.g., finding all contacts with an email ending in @msk.in).

Solution

1def find_contacts_by_domain(contacts, domain):
2    target = f"@{domain.lower().lstrip('@')}"
3    return [c for c in contacts if c.get("email", "").lower().endswith(target)]
4 
5# Sample test
6test_contacts = [
7    {"name": "Aarav", "email": "aarav@msk.in"},
8    {"name": "Priya", "email": "priya@google.com"},
9    {"name": "Rohan", "email": "rohan@msk.in"}
10]
11 
12matched = find_contacts_by_domain(test_contacts, "msk.in")
13print(f"Found {len(matched)} matching contacts:")
14for c in matched:
15    print(f"- {c['name']} ({c['email']})")

Expected Output

1Found 2 matching contacts:
2- Aarav (aarav@msk.in)
3- Rohan (rohan@msk.in)

Interactive Quiz• Knowledge Check

Practice Quiz

Question 1

In our Contact Manager, what happens if contacts.csv does not exist when the program boots?

Question 2

How does the delete_contact() function remove a record from the CSV file?

Question 3

Why is newline='' supplied to open() during both load and save operations?

Question 4

Which method of csv.DictWriter writes all dictionary rows in a single step?

Question 5

Why is csv.DictReader preferred over index-based csv.reader for storing entities with multiple attributes like contacts?

🚀 What's Next?

In the next lesson, we will continue your intermediate Python journey with Creating Classes & Objects (Review) (5: Object-Oriented Programming (Intermediate)).

👉 Continue to Next Lesson: Creating Classes & Objects (Review) →

Next Lesson

Creating Classes & Objects (Review)

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

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Creating Classes & Objects (Review)

Project: CSV Contact Manager in Python

Intermediate8 min read•Updated: 2026-10-01

Study Materials Cheatsheet

Project: CSV Contact Manager

1. Project Specifications & Requirements

The application will manage contact records and save them to contacts.csv. Key capabilities:

1
Data Persistence: Automatically reads from and writes to a structured CSV file.
2
Auto-Initialization: Gracefully initializes the CSV file with headers if it does not yet exist.
3
Core CRUD Operations:

Create: Add new contacts with validation.
Read: Display all contacts in a formatted table.
Search: Case-insensitive search by name or category.
Delete: Remove a contact by name and rewrite the updated dataset.

1
Safety: Handles missing files, invalid inputs, and file permissions without crashing.

2. Complete Application Code

1import csv
2import os
3 
4CSV_FILE = "contacts.csv"
5FIELDNAMES = ["name", "phone", "email", "category"]
6 
7 
8def initialize_storage():
  """Ensures the CSV file exists with the proper column headers."""
  if not os.path.exists(CSV_FILE):
      try:
          with open(CSV_FILE, mode="w", encoding="utf-8", newline="") as f:
              writer = csv.DictWriter(f, fieldnames=FIELDNAMES)
              writer.writeheader()
      except OSError as err:
          print(f"Error initializing contact database: {err}")
17 
18 
19def load_contacts():
  """Loads and returns all contacts as a list of dictionaries."""
  contacts = []
  try:
      with open(CSV_FILE, mode="r", encoding="utf-8", newline="") as f:
          reader = csv.DictReader(f)
          for row in reader:
              contacts.append(row)
  except FileNotFoundError:
      initialize_storage()
  except OSError as err:
      print(f"Error reading {CSV_FILE}: {err}")
  return contacts
32 
33 
34def save_contacts(contacts):
  """Overwrites the CSV file with the provided list of contact dictionaries."""
  try:
      with open(CSV_FILE, mode="w", encoding="utf-8", newline="") as f:
          writer = csv.DictWriter(f, fieldnames=FIELDNAMES)
          writer.writeheader()
          writer.writerows(contacts)
      return True
  except OSError as err:
      print(f"Failed to save contacts: {err}")
      return False
45 
46 
47def add_contact():
  """Prompts for contact details and appends to CSV."""
  print("\n--- Add New Contact ---")
  name = input("Enter Full Name: ").strip()
  phone = input("Enter Phone Number: ").strip()
  email = input("Enter Email Address: ").strip()
  category = input("Enter Category (Family/Work/Friend): ").strip().capitalize()
54 
  if not name or not phone:
      print("Error: Name and Phone number are required fields!")
      return
58 
  contacts = load_contacts()
  
  # Check for duplicate names
  if any(c["name"].lower() == name.lower() for c in contacts):
      print(f"A contact named '{name}' already exists.")
      return
65 
  new_contact = {
      "name": name,
      "phone": phone,
      "email": email or "N/A",
      "category": category or "General"
  }
72 
  contacts.append(new_contact)
  if save_contacts(contacts):
      print(f"Contact '{name}' added successfully!")
76 
77 
78def view_contacts():
  """Displays all contacts in a formatted table."""
  contacts = load_contacts()
  if not contacts:
      print("\nNo contacts found. Add one first!")
      return
84 
  print("\n" + "=" * 65)
  print(f"{'NAME':<20} | {'PHONE':<15} | {'CATEGORY':<10} | {'EMAIL'}")
  print("-" * 65)
  for c in contacts:
      print(f"{c['name']:<20} | {c['phone']:<15} | {c['category']:<10} | {c['email']}")
  print("=" * 65)
91 
92 
93def search_contact():
  """Searches contacts by name or category substring."""
  query = input("\nEnter search term (name or category): ").strip().lower()
  contacts = load_contacts()
  
  results = [
      c for c in contacts 
      if query in c["name"].lower() or query in c["category"].lower()
  ]
102 
  if not results:
      print(f"No contacts matching '{query}'.")
      return
106 
  print(f"\nFound {len(results)} match(es):")
  for c in results:
      print(f" - {c['name']} ({c['category']}): {c['phone']} | {c['email']}")
110 
111 
112def delete_contact():
  """Deletes a contact by exact name."""
  name_to_delete = input("\nEnter exact name of contact to delete: ").strip().lower()
  contacts = load_contacts()
  
  initial_count = len(contacts)
  updated_contacts = [c for c in contacts if c["name"].lower() != name_to_delete]
119 
  if len(updated_contacts) == initial_count:
      print(f"No contact found with name '{name_to_delete}'.")
  else:
      if save_contacts(updated_contacts):
          print("Contact deleted successfully.")
125 
126 
127def main_menu():
  """Main user interaction loop."""
  initialize_storage()
  
  while True:
      print("\n===== CONTACT MANAGER (CSV) =====")
      print("1. View All Contacts")
      print("2. Add New Contact")
      print("3. Search Contact")
      print("4. Delete Contact")
      print("5. Exit")
138 
      choice = input("Select an option (1-5): ").strip()
140 
      if choice == "1":
          view_contacts()
      elif choice == "2":
          add_contact()
      elif choice == "3":
          search_contact()
      elif choice == "4":
          delete_contact()
      elif choice == "5":
          print("Exiting Contact Manager. Goodbye!")
          break
      else:
          print("Invalid choice. Please choose between 1 and 5.")
154 
155 
156if __name__ == "__main__":
  main_menu()

3. Sample Execution Output

1===== CONTACT MANAGER (CSV) =====
21. View All Contacts
32. Add New Contact
43. Search Contact
54. Delete Contact
65. Exit
7Select an option (1-5): 2
8 
9--- Add New Contact ---
10Enter Full Name: Anita Desai
11Enter Phone Number: +91-9876543210
12Enter Email Address: anita@example.com
13Enter Category (Family/Work/Friend): Work
14Contact 'Anita Desai' added successfully!
15 
16===== CONTACT MANAGER (CSV) =====
171. View All Contacts
182. Add New Contact
193. Search Contact
204. Delete Contact
215. Exit
22Select an option (1-5): 1
23 
24=================================================================
25NAME                 | PHONE           | CATEGORY   | EMAIL
26-----------------------------------------------------------------
27Anita Desai          | +91-9876543210  | Work       | anita@example.com
28=================================================================

⚠️ Common Intermediate Mistakes & Gotchas

1. Corrupting Data During Mid-Write Crashes

2. Case-Sensitive Search Mismatches

Always normalize search strings and contact names using .lower().strip() before comparison to ensure reliable search results.

💻 Try It Yourself: Extension Challenge - Contact Export

Challenge

Extend the Contact Manager to add a search filter method that finds contacts by company domain name (e.g., finding all contacts with an email ending in @msk.in).

Solution

1def find_contacts_by_domain(contacts, domain):
2    target = f"@{domain.lower().lstrip('@')}"
3    return [c for c in contacts if c.get("email", "").lower().endswith(target)]
4 
5# Sample test
6test_contacts = [
7    {"name": "Aarav", "email": "aarav@msk.in"},
8    {"name": "Priya", "email": "priya@google.com"},
9    {"name": "Rohan", "email": "rohan@msk.in"}
10]
11 
12matched = find_contacts_by_domain(test_contacts, "msk.in")
13print(f"Found {len(matched)} matching contacts:")
14for c in matched:
15    print(f"- {c['name']} ({c['email']})")

Expected Output

1Found 2 matching contacts:
2- Aarav (aarav@msk.in)
3- Rohan (rohan@msk.in)

Interactive Quiz• Knowledge Check

Practice Quiz

Question 1

In our Contact Manager, what happens if contacts.csv does not exist when the program boots?

Question 2

How does the delete_contact() function remove a record from the CSV file?

Question 3

Why is newline='' supplied to open() during both load and save operations?

Question 4

Which method of csv.DictWriter writes all dictionary rows in a single step?

Question 5

Why is csv.DictReader preferred over index-based csv.reader for storing entities with multiple attributes like contacts?

🚀 What's Next?

In the next lesson, we will continue your intermediate Python journey with Creating Classes & Objects (Review) (5: Object-Oriented Programming (Intermediate)).

👉 Continue to Next Lesson: Creating Classes & Objects (Review) →

Next Lesson

Creating Classes & Objects (Review)

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

Related Lessons

Previous Lesson	Next Lesson
Modern Filesystem Handling with pathlib.Path	Creating Classes & Objects (Review)

Practice Quiz

Test your understanding of this lesson with 5 questions. Each question has one correct answer.

Previous Next