To apply expectations only if a column exists in Delta Live Tables (DLT), you can use the @Dlt.expect decorator conditionally within your Python function. Here is a step-by-step approach to achieve this:

1. Check if the Column Exists: Before applying the expectation, check if the column exists in the DataFrame.
2. Apply Expectations Conditionally: Use the @Dlt.expect decorator only if the column is present.