Santosh Srinivas wrote: > > A fundamental question ...I'm trying to understand the differences between > loop and vectorization ... I understand that it should be a natural choice > to use apply / adply when it is needed to perform the > same function across all rows of a data frame. Any pointers on why this is > so? Unable to find the right reading place on the WWW which explains the > concept. >
Strange. "loop vectorization" gives a few hundred of hits, that tell you that loops are not as bad in R (compared to S) in many cases. "apply" is probably the least important vectorization method in R, but I admit that some texts make us believe that it is the point where you show your R-talents. "adply" is different: it is a rather complex function from package plyr by Hadley Wickham. This package provides some elegant orthogonal functions under a unified concept. I found it appealing at the first look, but I am less frequently using it nowadays because it can be terribly slow. Try the chapter in http://www.burns-stat.com/pages/Tutor/R_inferno.pdf Dieter -- View this message in context: http://r.789695.n4.nabble.com/Difference-between-loops-and-vectorization-tp3066585p3066788.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
