We have a guy at work who uses J for everything, since he came of age doing data analysis in APL, when APL was the only interpreted and powerful matrix language

We have a guy at work who uses J for everything, since he came of age doing data analysis in APL, when APL was the only interpreted and powerful matrix language out there. (Fortran was compiled and low level.) He loves it, but he doesn't know any other languages. Personally, I found J a very interesting interesting exercise, and APL is historically SUPER important, but for practical uses they have been way superseded by matlab/ Octave/ R and the T/P/R* scripting languages. (At times my friend will say something like "in J you can compute the sum of a matrix IN JUST ONE LINE... and I will point to "sum(A)" in matlab, as opposed "$&$%^%$%M" in J, or whatever it is.) K may be more brain friendly than J. But as far as I am concerned, J makes assembler and badly written Perl look easy to read.