An interviewer may ask you to predict a DataFrame result before asking you to write code. Start with the shape: which rows survive, which columns remain and what missing values mean. A column expression describes work for Spark; it is not the same as a Python Boolean or a list of values collected into local memory.
These six questions combine short notebook tasks with code-reading decisions. Write the result before checking the answer, and explain your reasoning aloud if you are practicing with another person. The notebook tasks use Aster Supply's orders, including a missing amount, a missing buyer and a refund. Those records are intentional. A correct answer handles them according to the prompt rather than removing every inconvenient row. In a real interview, state any data contract you need before assuming it.