Imagine I've defined the following name in J: m =: >: i. 2 4 5 This looks like the following: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 I want to create a monadic verb of rank 1 that applies to each list in this list of lists. It will double (+:) or add 1 ...
If you're not familiar with the Rowland prime sequence, you can find out about it here. I've created an ugly, procedural monadic verb in J to generate the first n terms in this sequence, as follows: rowland =: monad define result =. 0 $ 0 t =. 1 $ 7 while. (# result) < y do. a =. {: t n =. 1 + # t t =...
I've solved 84 of the Project Euler problems, mostly in Haskell. I am now going back and trying to solve in J some of those I already solved in Haskell, as an exercise in learning J. Currently, I am trying to solve Problem 56. Let me stress that I already know what the right answer is, since I've already solved it in Haskell. It's a ver...
I want to be able to read and write files, etc. How can I do this? ...
Hi, I come from a background of C, Fortran, Python, R, Matlab, and some Lisp - and I've read a few things on Haskell. What are some neat ideas/examples in J or other languages from the APL family that are unique and not implemented in more common languages? I'm always interested in finding out what I'm missing... ...
I'm learning how to use J via online reading and doing some old Java assignments over again using this language, and would like to know how to make a verb that doesn't take any operands, or return any result. The reason being: I would like to allow myself the ability to type in a verb, let's call it go that would run a sequence of code o...
I have been learning the Factor and J languages to experiment with point-free programming. The basic mechanics of the languages seem clear, but getting a feeling for how to approach algorithm design is a challenge. A particular source of confusion for me is how one should structure code so that it is easy to experiment with different pa...