daru

Works across all Ruby versions without external dependencies, as stated in the README, ensuring easy adoption in any Ruby environment.

Supports singly and hierarchically indexed data structures, enabling complex manipulations like time series and categorical data, detailed in notebooks.

Seamlessly works with IRuby notebooks, statsample for statistics, and plotting libraries like Nyaplot, facilitating interactive analysis and visualization.

Offers intuitive APIs for splitting, aggregation, grouping, and pivot tables, as shown in examples with where clauses and column operations.