**Example 1 (Parse date)**: `@udf("date")`; `def parse_date(s): return datetime.strptime(s, "%Y-%m-%d").date()`
**Example 2 (Pandas UDF, vectorized)**: `@pandas_udf("double")`; `def scale(s: pd.Series) -> pd.Series: return s * 2`
**Example 3 (UDAF)**: Custom aggregate; GroupedData.agg(custom_udaf(col)).
**Production**: Prefer built-in. Pandas UDF for performance. Register and reuse. Test null handling.
**Scalability Trade-offs**: Python UDF slow; Pandas UDF 5–20x faster....
The complete answer continues with detailed implementation patterns, architectural trade-offs, and production-grade considerations. It covers performance optimization strategies, common pitfalls to avoid, and real-world examples from companies like LTIMindtree. The answer also includes follow-up discussion points that interviewers commonly explore.
Continue Reading the Full Answer
Unlock the complete expert answer with code examples, trade-offs, and pro tips - plus 1,863+ more.
Or upgrade to Platform Pro - $39
Engineers who used these answers got offers at
AmazonDatabricksSnowflakeGoogleMeta
According to DataEngPrep.tech, this is one of the most frequently asked Spark/Big Data interview questions, reported at 1 company. DataEngPrep.tech maintains a curated database of 1,863+ real data engineering interview questions across 7 categories, verified by industry professionals.