oehl_list@gmx.de
2002-Nov-07 19:10 UTC
[R] language inconsistency puzzle (in the tradition of Bill Venables (Hi Bill) puzzle "what is x")
> # let's say we have two vectors a and b > # lets make a copy of a > > a2 <- a > > # not surprisingly > identical(a[b], a2[b])[1] TRUE> > # now assigning same to same > a[b] <- a2[b] > > # and SURPRISE > identical(a, a2)[1] FALSE>WHAT IS a AND b ? Hint: this "works" under 1.5.1 and 1.6.1. However, the final value of a will differ between 1.5.1 and 1.6.1 under certain circumstances. Explain why it is both, DOUBLY INCONSISTENT AND UNAVOIDABLE. BTW, the prototype does the same. The serious side of this: I think the situation deserves at least a WARNING. Best Jens Oehlschl?gel -- -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._