Short version: K is a tight, fast exercise in minimalism. It takes after Scheme a bit more than most other APLs. Good at dealing with "ragged" and mixed-type da

Short version: K is a tight, fast exercise in minimalism. It takes after Scheme a bit more than most other APLs. Good at dealing with "ragged" and mixed-type data. J is a larger language with more "batteries included". It keeps the traditional APL emphasis on uniform, rectangular data and has a number of advanced features.