Dear all, I am a bit surprised that R does not give a warning (or a message error) when calling, in a data.frame (or a list), an element that does not exist:
temp <- data.frame(my.var1 = c(1,2), my.var2 = c(3,4)) temp
my.var1 my.var2 1 1 3 2 2 4
temp$my.var3 ### it does not exist
NULL
my.vect <- c(temp$my.var1, temp$my.var3) ### no marning my.vect
[1] 1 2 I would expect a message saying that my.var3 is NULL when trying to manipulate it. For instance, sum() gives:
sum(temp$my.var3)
[1] 0 (the same with any suffix after $) which is again surprising since, to me, the element does not exist. Is there a reason for this? Best, Emmanuel Paradis -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- 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 _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._