Hello, Inline.
Em 05-12-2016 17:09, David Winsemius escreveu:
On Dec 5, 2016, at 7:29 AM, John Sorkin <jsor...@grecc.umaryland.edu> wrote: Rui, I appreciate your suggestion, but eliminating the deparse statement does not solve my problem. Do you have any other suggestions? See code below. Thank you, John mydf <- data.frame(id=c(1,2,3,4,5),sex=c("M","M","M","F","F"),age=c(20,34,43,32,21)) mydf class(mydf) myfun <- function(frame,var){ call <- match.call() print(call) indx <- match(c("frame","var"),names(call),nomatch=0) print(indx) if(indx[1]==0) stop("Function called without sufficient arguments!") cat("I can get the name of the dataframe as a text string!\n") #xx <- deparse(substitute(frame)) print(xx) cat("I can get the name of the column as a text string!\n") #yy <- deparse(substitute(var)) print(yy) # This does not work. print(frame[,var]) # This does not work. print(frame[,"var"]) # This does not work. col <- xx[,"yy"] # Nor does this work. col <- xx[,yy] print(col) } myfun(mydf,age)When you use that calling syntax, the system will supply the values of whatever the `age` variable contains. (And if there is no `age`-named object, you get an error at the time of the call to `myfun`.
Actually, no, which was very surprising to me but John's code worked (not the function, the call). And with the change I've proposed, it worked flawlessly. No errors. Why I don't know.
Rui Barradas You need either to call it as:
myfun( mydf , "age") # Or: age <- "age" myfun( mydf, age) Unless your value of the `age`-named variable was "age" in the calling environment (and you did not give us that value in either of your postings), you would fail.
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