When working with Outlook in Python, you may come across the need to add existing contacts to a distribution list. This can be achieved in different ways, depending on your specific requirements and the libraries you are using. In this article, we will explore three different options to solve this problem.

Option 1: Using the win32com.client Library

The win32com.client library provides a way to interact with the Outlook application using COM automation. To add existing contacts to a distribution list, you can follow these steps:

import win32com.client

# Connect to Outlook
outlook = win32com.client.Dispatch("Outlook.Application")

# Get the distribution list
dist_list = outlook.Session.GetDefaultFolder(10).Items.Item("Distribution List Name")

# Get the contacts to add
contacts = outlook.Session.GetDefaultFolder(10).Items

# Iterate over the contacts and add them to the distribution list
for contact in contacts:
    if contact.FullName in ["Contact 1", "Contact 2", "Contact 3"]:
        dist_list.AddMember(contact)

This code snippet connects to Outlook, retrieves the distribution list by name, and then iterates over the contacts to add them to the distribution list. You can modify the list of contacts to add by updating the condition in the if statement.

Option 2: Using the O365 Library

The O365 library is a Python wrapper for the Microsoft Graph API, which allows you to interact with various Microsoft services, including Outlook. To add existing contacts to a distribution list using this library, you can follow these steps:

from O365 import Account

# Connect to Outlook
credentials = ('client_id', 'client_secret')
account = Account(credentials)
if not account.is_authenticated:
    account.authenticate(scopes=['basic', 'message_all'])

# Get the distribution list
dist_list = account.schedule().get_default_calendar().get_distribution_list("Distribution List Name")

# Get the contacts to add
contacts = account.directory().get_contacts()

# Iterate over the contacts and add them to the distribution list
for contact in contacts:
    if contact.display_name in ["Contact 1", "Contact 2", "Contact 3"]:
        dist_list.add_member(contact)

This code snippet connects to Outlook using the provided client ID and client secret, retrieves the distribution list by name, and then iterates over the contacts to add them to the distribution list. You can modify the list of contacts to add by updating the condition in the if statement.

Option 3: Using the exchangelib Library

The exchangelib library is another Python library that provides a high-level interface for working with Exchange Web Services (EWS). To add existing contacts to a distribution list using this library, you can follow these steps:

from exchangelib import DELEGATE, Account, Credentials

# Connect to Outlook
credentials = Credentials(username='email@example.com', password='password')
account = Account(primary_smtp_address='email@example.com', credentials=credentials, autodiscover=True, access_type=DELEGATE)

# Get the distribution list
dist_list = account.distribution_lists.get("Distribution List Name")

# Get the contacts to add
contacts = account.contacts.all()

# Iterate over the contacts and add them to the distribution list
for contact in contacts:
    if contact.fullname in ["Contact 1", "Contact 2", "Contact 3"]:
        dist_list.members.append(contact)

# Save the changes
dist_list.save()

This code snippet connects to Outlook using the provided email and password, retrieves the distribution list by name, and then iterates over the contacts to add them to the distribution list. You can modify the list of contacts to add by updating the condition in the if statement.

After exploring these three options, it is difficult to determine which one is better as it depends on your specific requirements and the libraries you are already using in your project. However, if you are starting a new project or have the flexibility to choose, the O365 library provides a more modern and comprehensive approach by leveraging the Microsoft Graph API. It offers a wider range of functionalities and better integration with other Microsoft services. Therefore, Option 2 using the O365 library may be the preferred choice for most scenarios.