How do I merge two dictionaries in a single expression?

You can use the update() method of one dictionary to merge the key-value pairs from another dictionary into it. For example:

merge dictionaries by update method in Python

Alternatively, you can use the {**d1, **d2} syntax to create a new dictionary that contains the key-value pairs from both d1 and d2. This syntax is available in Python 3.5 and newer.

merge dictionaries by ** in Python

This syntax is known as the double-starred dictionary (or "unpacking") syntax. It allows you to expand the key-value pairs in one dictionary into another dictionary.