the step is calculated rather than given you’d need to preprocess the argument(s)
Am 02.04.20 um 01:26 schrieb Fraser Jackson:
No one has mentioned the simple function load 'stats/base' steps 5 19 14 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 steps 5 9 8 5 5.5 6 6.5 7 7.5 8 8.5 9 steps _3 10 13 _3 _2 _1 0 1 2 3 4 5 6 7 8 9 10 steps 4.25 8.75 9 4.25 4.75 5.25 5.75 6.25 6.75 7.25 7.75 8.25 8.75 steps 9 4 5 9 8 7 6 5 4 Also useful for a wide variety of other cases Sent from Mail for Windows 10 From: Don Kelly Sent: Thursday, April 2, 2020 10:27 AM To: [email protected] Subject: Re: [Jprogramming] generate integers from a to be with a step I like this and find your approach to thru interesting as it works both ways 5 thru 19 and 19 thru 5. A 'one way' approach could be this thru2=. }. [:i.>: 5 thru2 19 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 some time difference but no space difference (100)6!:2 '5 thru2 200' 1.117e_6 (100)6!:2 '5 thru 200' 1.44e_6 reverse |. 5 thru2 19 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 Don On 2020-03-29 7:34 a.m., Raul Miller wrote:As your examples illustrate, this is something of an underspecified problem. But let's try a few things... First, there's your basic i. which gets us a sequence: i.1+14 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 And adding step 3 means taking fewer steps and making them longer 3*i.<.1+14%3 0 3 6 9 12 And we can of course add our starting point back in: 5+3*i.<.1+14%3 5 8 11 14 17 Meanwhile, without step, we can make a dyad to give us all integers in a range: thru=: <. + i.@(+ *)@-~ 5 thru 19 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 19 thru 5 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 With step, what would this look like? (#~ 0= 3|]) 5 thru 19 6 9 12 15 18 (#~ 0= 3|5-~]) 5 thru 19 5 8 11 14 17 (#~ 0= 3|19-~]) 5 thru 19 7 10 13 16 19 Let's pick the second one (since it matches an example you gave) and parameterize that. Specifically, let's declare our arguments like this: step stepThrough start,limit ('step', 'start' and 'limit' are all single integers here, and 'stepThrough' will be our verb) I can't see any non-verbose ways of making this tacit, so: stepThrough=:dyad define 'start diff'=. -/\ y start-(*diff)*x*i.<.1+x%~|diff ) 3 stepThrough 5 19 5 8 11 14 17 3 stepThrough 19 5 19 16 13 10 7 Does the implementation seem a bit arbitrary? Well... it should. After all, we arbitrarily picked from one of several possible mechanisms which matched the description. But I hope this helps. (And, I hope email transport doesn't reformat what I've written.) Thanks,---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
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