Open source

A minimal-dependency Java implementation of Apache Parquet. I authored dictionary-space predicate evaluation, which evaluates a predicate once per column-chunk dictionary and answers rows by index comparison instead of decoding values (accepted, landing next release). I also restored Bloom filter pruning on FLOAT and DOUBLE columns, and packed the dive TUI preview by content width.

Contributed merged DataFrame API implementations — replace, cache, to_records, and to_excel — to Koalas, which was later merged into Apache Spark as the pandas API on Spark.

An open-source key-value store written in Python, built on the standard library's own primitives.

A small Python library for finding the roots of a cubic equation, used widely enough to pick up a few dozen stars.