**Flatten:** `[item for sublist in lists for item in sublist]` or `list(chain(*lists))`. **Range:** `[x for start,end in ranges for x in range(start,end+1)]`. **Nested:** Outer iterates first. **Why:** Readability; `chain` for many lists....
Pro-Move: chain.from_iterable for lazy flatten. Red Flag: Deep nested comprehensions hurting readability.
This easy-level Python/Coding question appears frequently in data engineering interviews at companies like Tiger Analytics. While less common, it tests deeper understanding that distinguishes strong candidates.
Start by clearly defining the core concept being asked about. Interviewers want to see that you understand the fundamentals before diving into implementation details. Structure your answer with a definition, then explain the practical application with a concise example.
Flatten: [item for sublist in lists for item in sublist] or list(chain(*lists)). Range: [x for start,end in ranges for x in range(start,end+1)]. Nested: Outer iterates first. Why: Readability; chain for many lists. Production: Prefer readability; avoid deep nesting.
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Analyze My Answer — FreeAccording to DataEngPrep.tech, this is one of the most frequently asked Python/Coding 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.