{"id":44633600,"url":"https://github.com/mathijs81/java-dataframes","last_synced_at":"2026-02-14T17:15:23.128Z","repository":{"id":146431628,"uuid":"149502517","full_name":"mathijs81/java-dataframes","owner":"mathijs81","description":"A quick test of a couple of data frame libraries for Java","archived":false,"fork":false,"pushed_at":"2025-06-05T17:53:53.000Z","size":434,"stargazers_count":21,"open_issues_count":1,"forks_count":11,"subscribers_count":1,"default_branch":"master","last_synced_at":"2025-06-05T18:42:35.974Z","etag":null,"topics":["dataframe","java-dataframe","toy-project"],"latest_commit_sha":null,"homepage":null,"language":"Jupyter Notebook","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":"apache-2.0","status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/mathijs81.png","metadata":{"files":{"readme":"README.md","changelog":null,"contributing":null,"funding":null,"license":"LICENSE","code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null,"governance":null,"roadmap":null,"authors":null,"dei":null,"publiccode":null,"codemeta":null,"zenodo":null}},"created_at":"2018-09-19T19:34:53.000Z","updated_at":"2025-06-05T17:53:55.000Z","dependencies_parsed_at":null,"dependency_job_id":"3ea47ee0-5be4-436e-85d2-2bce65ef9cee","html_url":"https://github.com/mathijs81/java-dataframes","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"purl":"pkg:github/mathijs81/java-dataframes","repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/mathijs81%2Fjava-dataframes","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/mathijs81%2Fjava-dataframes/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/mathijs81%2Fjava-dataframes/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/mathijs81%2Fjava-dataframes/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/mathijs81","download_url":"https://codeload.github.com/mathijs81/java-dataframes/tar.gz/refs/heads/master","sbom_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/mathijs81%2Fjava-dataframes/sbom","scorecard":null,"host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":286080680,"owners_count":29450845,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2026-02-14T15:52:44.973Z","status":"ssl_error","status_checked_at":"2026-02-14T15:52:11.208Z","response_time":53,"last_error":"SSL_connect returned=1 errno=0 peeraddr=140.82.121.6:443 state=error: unexpected eof while reading","robots_txt_status":"success","robots_txt_updated_at":"2025-07-24T06:49:26.215Z","robots_txt_url":"https://github.com/robots.txt","online":false,"can_crawl_api":true,"host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":["dataframe","java-dataframe","toy-project"],"created_at":"2026-02-14T17:15:22.535Z","updated_at":"2026-02-14T17:15:23.116Z","avatar_url":"https://github.com/mathijs81.png","language":"Jupyter Notebook","funding_links":[],"categories":[],"sub_categories":[],"readme":"# Java dataframes test\nThis is the companion repository to the following medium post: [Doing cool data science in Java: how 3 DataFrame libraries stack up](https://medium.com/@thijser/doing-cool-data-science-in-java-how-3-dataframe-libraries-stack-up-5e6ccb7b437)\n\n## Data\nThe data was extracted from [Eurostat](http://appsso.eurostat.ec.europa.eu/nui/show.do?dataset=urb_cpop1\u0026lang=en) in the beginning of September 2018. I opened the extracted CSV in LibreOffice and saved it again because there were some illegal UTF-8 characters in the Eurostat output that some csv importers couldn't handle directly.\n\n# Results [June 2025]\n\n| Library                                                 | Maintained | Version   | Time (ms) |\n|---------------------------------------------------------|------------|-----------|-----------|\n| [DuckDb](https://github.com/duckdb/duckdb-java)         | Y          | 1.3.0     | 93        |\n| [DFLib](https://github.com/dflib/dflib)                 | Y          | 1.3.0     | 226       |\n| [Kotlin DataFrame](https://github.com/Kotlin/dataframe) | Y          | 1.0-beta2 | 816       |\n| [Tablesaw](https://github.com/jtablesaw/tablesaw)       | Y          | 0.44.1    | 820       |\n| Joinery                                                 | n          | 1.9       | 1,478     |\n| Krangl                                                  | n          | 0.18.4    | 1,796     |\n| Morpheus                                                | n          | 0.9.23    | *         |\n\n* Morpheus is no longer maintained and doesn't seem to work on later java versions (error related to accessing `sun.util.calendar.ZoneInfo`)\n\n## Code\nThe code for the three libraries is present in the `Test{libraryname}.java` files. They all use `CheckResult.java` to do a basic correctness check for the top-growing cities.\n\nAs described in the [medium post](https://medium.com/@thijser/doing-cool-data-science-in-java-how-3-dataframe-libraries-stack-up-5e6ccb7b437), I couldn't find a good way to do the pivot step in [datavec](https://deeplearning4j.org/docs/latest/datavec-overview), but I included the code I wrote up until that point.\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fmathijs81%2Fjava-dataframes","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fmathijs81%2Fjava-dataframes","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fmathijs81%2Fjava-dataframes/lists"}