You can merge two dictionaries in a single expression using the update() method in Python. Here's an example:

dict1 = {"a": 1, "b": 2}
dict2 = {"c": 3, "d": 4}

merged_dict = {**dict1, **dict2}
# or

merged_dict = dict1

In the first example, the ** operator unpacks the contents of both dictionaries into a new dictionary, effectively merging them. In the second example, the update() method is used to update dict1 with the contents of dict2, effectively merging them in place. The resulting merged dictionary is stored in merged_dict.

print(merged_dict)  # Output: {'a': 1, 'b': 2, 'c': 3, 'd': 4}