I was recently caught out when I assumed(presumed?) that if y1 is an initial sublist of y2 , then ?.y1 would be an initial sublist of ?.y2 . This is usually the case, but not when y1 is a list of fewer than 28n 2s and y2 is a list of at least 28n 2s, where n is a positive integer. Thus:
?. 27#2 0 1 1 0 0 1 0 1 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 1 1 ?. 28#2 0 1 0 1 1 1 0 0 0 1 0 1 0 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 list ?. 55#2 0 1 0 1 1 1 0 0 0 1 0 1 0 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 1 0 0 1 0 1 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 1 1 1 list ?. 56#2 0 1 0 1 1 1 0 0 0 1 0 1 0 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 1 0 1 1 0 0 1 0 0 1 0 1 0 0 0 0 1 0 1 0 0 1 0 0 1 0 0 list ?. 111#2 0 1 0 1 1 1 0 0 0 1 0 1 0 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 1 0 1 1 0 0 1 0 0 1 0 1 0 0 0 0 1 0 1 0 0 1 0 0 1 0 0 1 1 0 0 1 0 1 0 1 1 0 0 1 1 0 0 1 0 1 0 1 0 1 0 1 0 0 1 0 0 1 0 1 0 0 0 0 1 0 1 0 0 0 0 0 1 0 0 0 0 1 1 1 0 0 list ?. 112#2 0 1 0 1 1 1 0 0 0 1 0 1 0 0 1 0 0 0 0 0 1 1 1 0 0 0 0 0 1 1 0 1 1 0 0 1 0 0 1 0 1 0 0 0 0 1 0 1 0 0 1 0 0 1 0 0 1 1 0 0 1 0 1 0 1 1 0 0 1 1 0 0 1 0 1 0 1 0 1 0 1 0 0 1 0 0 1 0 0 1 1 1 1 0 1 0 0 0 0 0 1 0 1 1 1 0 1 1 1 1 0 1 I don't think this behaviour contradicts any documentation, but also I don't think it is documented anywhere, and it may catch someone else unawares! Regards, Ewart J.E.H.Shaw http://www.warwick.ac.uk/statsdept Ewart Shaw http://www.ewartshaw.co.uk ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
