How to Select Objects in Django Models with Regular Expressions email__regex=^\w{1,5}@

In Django, you can use the regex lookup to filter objects based on regular expressions. This is particularly useful for complex queries, such as matching strings that contain specific patterns like "info@", "contact@", "test@", "team@", "msg@", or any other pattern.

1. Install Django if you haven't already:

pip install django

2. Set up a Django model:

Suppose you have a model called EmailModel with a field email that you want to filter.


from django.db import models

class EmailModel(models.Model):
    email = models.CharField(max_length=255)

3. Use the `regex` lookup to filter your objects:

You can use the filter() method with the regex lookup to match emails containing specific patterns. For example, to find emails that contain the pattern info@ or ms@, you can do the following:


from myapp.models import EmailModel

# Match emails containing 'info@'
info_emails = EmailModel.objects.filter(email__regex=r'info@')

# Match emails containing 'ms@'
ms_emails = EmailModel.objects.filter(email__regex=r'ms@')

4. For more complex regular expressions:

If you want to match a pattern with exactly 3 letters followed by an @ character, you can use a more complex regex pattern.


# Match emails with exactly 3 letters before '@'
three_letters_emails = EmailModel.objects.filter(email__regex=r'\b[A-Za-z]{3}@')

5. Combine multiple patterns:

If you want to find all objects that match either info@ or ms@, you can combine the queries using the Q object.


from django.db.models import Q

combined_emails = EmailModel.objects.filter(
    Q(email__regex=r'info@') | Q(email__regex=r'ms@')
)

Example of a Full Django QuerySet

Here's how you might write a full function to retrieve and print these emails:


from django.db.models import Q
from myapp.models import EmailModel

def get_emails():
    # Query for emails containing 'info@'
    info_emails = EmailModel.objects.filter(email__regex=r'info@')
    print("Emails containing 'info@':")
    for email in info_emails:
        print(email.email)
    
    # Query for emails containing 'ms@'
    ms_emails = EmailModel.objects.filter(email__regex=r'ms@')
    print("Emails containing 'ms@':")
    for email in ms_emails:
        print(email.email)
    
    # Combined query
    combined_emails = EmailModel.objects.filter(
        Q(email__regex=r'info@') | Q(email__regex=r'ms@')
    )
    print("Emails containing 'info@' or 'ms@':")
    for email in combined_emails:
        print(email.email)

# Call the function
get_emails()

This code will filter your EmailModel objects based on the provided regular expressions and print the matching emails. Adjust the regular expressions as needed to fit your specific pattern requirements.

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