Beyond Arrays: PowerShell Collections for Speed & Scale
summary
Shows concrete swaps and measured wins: choose Generic Lists over arrays for resizable typed collections, use HashSet to deduplicate 10,000 items in ~1 ms versus Select-Object -Unique ~500 ms, and replace Where-object scans with hash-based lookups so CSV comparisons drop from ~19,000 ms to ~275 ms (~69×). Mentions array improvements in PowerShell 7.5 PR 23901, demos batching with Queue, undo with Stack, and handling millions of items (3 million tenant) to prove when each collection actually scales.
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chapters (22)
- 0:00PowerShell collections intro
- 1:12Arrays fixed size limits
- 2:39ArrayList legacy issues
- 3:21Lists modern replacements
- 5:53Array performance demo
- 8:44PowerShell 7.5 array performance improvements
- 11:33Generic lists type safety
- 13:00List operations methods
- 17:04Hash tables dictionaries
- 21:41Hash sets deduplication
- 23:48Hash table benchmarks
- 27:24Dictionary try get value method
- 29:49Group-Object with hashes
- 31:38Hash set deduplication demo
- 35:40Hash set set operations
- 36:44Hash set contains speed
- 38:10CSV columns with hash sets
- 40:15Queues and stacks
- 42:22Queue batch processing
- 47:48Stack undo operations
- 49:34Decision tree for collection selection
- 50:15Closing Q&A
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