Here's how you can extract all valid email addresses from the text and return them in a comma-separated list using Python: ```python import re text = """ Contact information: 1. John Doe - john.doe@example.com 2. Jane Smith - jane@smith-family.net 3. support@company.co.uk 4. info@subdomain.example.org 5. Invalid email: not.an.email.com 6. Another invalid: @missing-username.com """ # Regular expression pattern to match valid email addresses email_pattern = r'\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b' # Find all matches of email addresses in the text emails = re.findall(email_pattern, text) # Join the email addresses into a comma-separated string without spaces email_list = ','.join(emails) print(email_list) ``` Output: ``` john.doe@example.com,jane@smith-family.net,support@company.co.uk,info@subdomain.example.org ``` This code does the following: 1. It imports the `re` module to use regular expressions. 2. It defines the input text containing the contact information. 3. It creates a regular expression pattern `email_pattern` to match valid email addresses. The pattern ensures that: - The username part before the `@` symbol contains only alphanumeric characters, dots, underscores, percent signs, plus signs, or hyphens. - The domain part after the `@` symbol contains at least one dot and must have two or more alphabetic characters as the top-level domain. 4. It uses `re.findall()` to find all matches of the email pattern in the text and store them in the `emails` list. 5. It joins the email addresses in the `emails` list into a comma-separated string without spaces using `','.join(emails)`. 6. Finally, it prints the comma-separated list of valid email addresses. This approach ensures that only valid email addresses are extracted from the text and returned in the desired format. Let me know if you have any further questions!