Final answer:
Outputting to a lookup that already exists will generally overwrite the existing data with the new data; this is standard behavior in data manipulation and database operations.
Step-by-step explanation:
When discussing data manipulation or database operations, the question is about whether outputting to a lookup that already exists will overwrite it. The answer is generally True. If you output to a lookup (such as a key in a dictionary, a row in a database, or any other data structure that supports key-based assignment) and that lookup already exists, it will typically be overwritten with the new data that's provided. This is a common behavior in most programming languages and database systems when using constructs that allow the assignment of values based on a unique identifier or key.