If you're into fast cardinality estimation (HyperLogLog) and item counting (Count-min sketch, Bloom filters, hash tables), check out Bounter: https://github.co

If you're into fast cardinality estimation (HyperLogLog) and item counting (Count-min sketch, Bloom filters, hash tables), check out Bounter: https://github.com/RaRe-Technologies/bounter/ https://github.com/RaRe-Technologies/bounter/ (Pythonic interface on top of highly optimized algorithms, faster than dict but using limited memory, MIT license)