I'm convinced that data.table is wizardry. For anyone who's turned off by dt[i, j, by=k], Andrew Brooks has a good set of examples at http://brooksandrew.githu

I'm convinced that data.table is wizardry. For anyone who's turned off by dt[i, j, by=k], Andrew Brooks has a good set of examples at http://brooksandrew.github.io/simpleblog/articles/advanced-data-table/ http://brooksandrew.github.io/simpleblog/articles/advanced-d.... Data Camp's Cheat Sheet is also a good resource https://s3.amazonaws.com/assets.datacamp.com/blog_assets/datatable_Cheat_Sheet_R.pdf https://s3.amazonaws.com/assets.datacamp.com/blog_assets/dat....