Problem Statement
How do you build efficient collection transformation pipelines in Kotlin?
Explanation
Build transformation pipelines by chaining functional operations like filter, map, flatMap, and groupBy to process data declaratively. Each operation returns a new collection allowing method chaining, creating readable pipelines that clearly express data transformations step by step.
For performance with multiple operations on large collections, convert to sequence with asSequence to enable lazy evaluation, chain operations, then materialize results with terminal operations like toList or count. This avoids creating intermediate collections for each step.
Common patterns include filter to remove unwanted elements, map to transform, sortedBy to order, groupBy to categorize, and fold or reduce to aggregate. Use mapNotNull to transform and filter nulls in one step, and distinct to remove duplicates.
Keep pipelines readable by splitting very long chains across lines with each operation on its own line, and consider extracting complex transformations into named functions for reusability and testability.
Practice Sets
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