> -----Original Message----- > From: programming-boun...@forums.jsoftware.com [mailto:programming- > boun...@forums.jsoftware.com] On Behalf Of Martin Saurer > Sent: Friday, March 7, 2014 2:12 PM > To: programm...@jsoftware.com > Subject: Re: [Jprogramming] J in 5 minutes > > Hello all Jers, > My two cents (or 15 minutes) to show what J can do.
> https://www.youtube.com/watch?v=VSJpJt3c11c Quite nice! There are some things I find slightly misleading, but before I list them, I acknowledge the fact that some might be conscious choices to avoid possible confusion in an unprepared audience. This said... About Euler problem 1. Why use "E." and not the simpler "="? I can see that "=" can be "misleading" (to quote myself), but "=" is so common in J that one might as well get used to it from the beginning. So, my first suggestion would be to recast the solution as: +/ (i.1000) * (0 = 3|i.1000) +. (0 = 5|i.1000) Then, the similarity of the expressions in the brackets screams to me to be re-factored as: 0 = 3 5|/i.1000 to get to: +/ (i.1000) * +./0 = 3 5|/i.1000 Here I can see, even more than before, that this is overloading the meaning of "/". Still, in Euler 20 you go for an explicit rank, which you could use here to remove the ambiguity on the last "/". +/ (i.1000) * +./0 = 3 5|"0 _ ] i.1000 The cost for the beginner is the introduction of the bizzare "]" (which can be replaced safely with a + here): +/ (i.1000) * +./0 = 3 5|"0 _ + i.1000 and an early exposure to a reduction of a multidimensional array (the +./). Pros and cons... About Euler problem 20. If I had to write the code I'd definitely not go for the ,"0 and the execute. Instead I would: +/'0123456789' i. ": !100x 648 which I find more idiomatic. Or I would even go as far as using the inverse of 10 base. In other words, I'd show that: 10 #.^:_1 ] 134898 1 3 4 8 9 8 leads naturally to +/ 10 #.^:_1 !100x 648 My 1c worth.... All the best, -- Stefano ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
