How do I merge two dictionaries in a single expression

To merge two dictionaries in Python, use the update() method, the {**d1, **d2} unpacking syntax, or the | operator (Python 3.9+).

1. update(): Modifies the first dictionary (e.g., d1.update(d2)).
2. Unpacking: {**d1, **d2} creates a new dictionary, leaving the originals unchanged.
3. | Operator: Merges dictionaries into a new one without altering the originals (e.g., merged = d1 | d2).

When keys overlap, values from the second dictionary overwrite those from the first. Use these methods based on whether you need to preserve the original dictionaries or not.