f=: 13 :'+/!(($":y)#10)#:y' f 169 363601 Linda
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Raul Miller Sent: Thursday, September 04, 2014 5:39 PM To: Programming forum Subject: Re: [Jprogramming] repeated applications of a verb Just so it's clear what has happened here: ;:'SumOfFact^:3 169' +---------+--+-----+ |SumOfFact|^:|3 169| +---------+--+-----+ In other words, 3 169 is a single word. It's a word that happens to have a space in it, but that's actually not at all unusual. Here's another example of a word with a space in it: 'this is a test' Actually, that particular word has three spaces in it. But that counts, right? Note that some people prefer to call words "tokens" for various reasons. Note also that we train our eyes to see these things. To someone who has never studied computer programming languages, 'this is a test' might look like four words where two of them contain apostrophes. But someone familiar with quoting rules can see it as a single "thing" and - if they've played with implementations of parsers or similar things - they'll have an idea about why it's worth calling this thing a "word" or a "token". Anyways, I have had this happen to me relatively often, so I am familiar with its symptoms. I'll have a J sentence which uses a number and I will add another number to it, and I will want it to be a different word, and I have to remind myself to make it be one. Meanwhile some other messages have provided some examples of how to break 3 169 into two separate words, so I'll skip that part. But I'll note that I see four different ways of using a single pair of parenthesis to accomplish this. Thanks, -- Raul On Thu, Sep 4, 2014 at 2:55 PM, alessandro codenotti <[email protected]> wrote: > I'm working on PE#74, which asks for the sum of the factorials of the digits in a number > (i.e. if the number is 169 then it asks for 1!+6!+9!). > > I wrote this verb that performs the required operation: > SumOfFact=: 3 : 0 > +/!"."0@": y > ) > It works perfectly, but now I need to reiterate it to produce a chain like 169 -> 363601 -> 1454 -> 169,so I tried: > SumOfFact^:3 169 > > But instead of working as I hoped it simply writes "SumOfFact^:3 169" as output. > > What am I doing wrong and how am I supposed to repeatedly apply a verb to an argument? > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
