in Trains (ch.25) of old J introduction, it gave equivalent of cj=: [EMAIL PROTECTED] as CJ=: 2 : '(x f.\)@(y f.\)' I found that it also works even not using f. CJ1=: 2 : '(x\)@(y\)' (<) CJ (+/) a=.i. 3 3 +-----+-----+-------+ |0 1 2|0 1 2|0 1 2| | |3 5 7|3 5 7| | | |9 12 15| +-----+-----+-------+ (<) CJ1 (+/) a +-----+-----+-------+ |0 1 2|0 1 2|0 1 2| | |3 5 7|3 5 7| | | |9 12 15| +-----+-----+-------+
What is the significance of f. and under what circumstance will CJ1 fail to emulate [EMAIL PROTECTED] ?
In orginal exercise of ch.19, f. is used after each x. but in J601 exercise of ch.18, f. is not used, Is there any language change that makes f. no longer needed?
PS. I suspect there is typo(s) in dictionary/intro18.htm even=: 2 : 0 -:@(xf. + [EMAIL PROTECTED]) ) it should be an adverb 1 : and xf. be x -- regards, bill ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
